





















DRAWING OF LEVER SAFETY-VALVE; APPROVED BY THE BOARD OF SUPERVISING 

INSPECTORS OF STEAM-VESSELS 
































































































































































REPORT 


SAFETY-VALVE TESTS, 

MADE AT THE 

U. S. NAVY YARD, WASHINGTON, D. C., 


SPECIAL COMMITTEE 

OF THE 


BOARD OF SUPERVISING INSPECTORS OF STEAM-VESSELS. 


SEPTEMBER, 1875 . 


WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1877 . 








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1908 




RESOLUTION. 


> 

a 


Whereas the Board of Supervising Inspectors at their annual meeting held at 
Washington in January, 1875, appointed a committee, in pursuance of a resolution 
adopted by said Board, to make tests of the efficiency of the various kinds of safety- 
valves for use on steam-boilers. The Committee have performed their duty and 
submitted their report, which was adopted by the Board; the report developing many 
things in regard to this important matter not heretofore generally known to the engi¬ 
neering fraternity. This report is anxiously looked for by engine-builders and 
engineers in the merchant and naval service of the United States and foreign coun¬ 
tries; therefore, 

Be it resolved, That the Honorable Secretary of the Treasury be requested to have 
twenty-five hundred copies of the report of the Special Committee on Safety-Valves 
published in pamphlet form, accompanied by the engravings of the valves tested. 

JAS. A. DUMONT, 

Supervising Inspector General, President. 

B. O. Carr, 

Supervising Inspector, Sixth District, Secretary . 




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REPORT OF THE SPECIAL COMMITTEE 

OF THE 

BOARD OF SUPERVISING INSPECTORS 

ON 

SAFETY-VALVE TESTS. 


In obedience to the annexed resolution of the Board of 
Supervising Inspectors of Steam-Vessels, adopted January 22, 
1875, and its subsequent action thereon, the committee respect¬ 
fully submit the following report of their acts under the 
authority of this resolution: 

“ RESOLUTION. 

“Whereas, it is important to the Steamboat-Inspection Ser¬ 
vice that all steam-boilers should be provided with efficient 
safety-valves; and 

“Whereas, this question of efficiency can only be deter¬ 
mined by a proper test of the various instruments claimed by 
their inventors to be efficient safety-valves; therefore, 

u Be it resolved , That a committee, consisting of five mem¬ 
bers of this Board, be appointed (of which the Supervising 
Inspector General shall be chairman) for the purpose of making 
a thorough test of all safety-valves which may be presented; 
and that the expenses incurred in making these tests be paid 
out of the funds of this service ” 

By a subsequent act of the Board, this committee was re¬ 
duced to three members, including the chairman, and ordered 
to report at the next annual meeting. . 

The Secretary of the Treasury having approved of this 
action of the Board, the chairman of the committee issued the 
following circular, and caused the same to be published in the 
principal newspapers in the country: 



6 


SAFETY-VALVE TESTS. 




“ CIRCULAR. 

“The Board of Supervising Inspectors of Steam-Vessels, at 
their last annual session in January, 1875, appointed a commit¬ 
tee to make an experimental test of all steam-boiler safety- 
valves which may be submitted for examination, and which are 
believed to embody principles of action superior to those of 
the safety-valves in common use. 

“The valves presented must have a uniform area of opening 
of five square inches, (2.525 inches in diameter,) and will be 
submitted to the following competitive examinations: 

“1. Capability of discharging any excess of steam above a 
fixed working pressure. 

“2. The limit of pressure within which the valve will open 
and close. 

“3. Uniformity of action at different pressures. 

“4. Reliability of action under continued use. 

“5. Simplicity of arrangement and facility of management. 

“The valves will be tested at a pressure of not less than twenty 
nor more than eighty pounds to the square inch, and are not 
required to be provided with an enclosing case. 

“All valves must be operated by the pressure of the steam; 
and the greatest diameter of opening for double-seated valves 
will be the same for single-seated valves. 

“The flanges for attaching to boiler must be eight inches in 
diameter, flat-faced, without bolt-holes. 

“The proposed tests will commence on the 13th day of Sep¬ 
tember, 1875, in the City of Washington, and all valves sub¬ 
mitted must be boxed and sent by express (charges prepaid) to 
Commodore T. H. Patterson, Commandant of the Navy Yard, 
Washington, D. C.; and enclosed with each valve will be a 
communication addressed to the Committee of Examination, 
setting forth what superiority is claimed for the valve therewith 
submitted, and signed by the person presenting the same. 

“All valves must be delivered on or before the 6th of Sep¬ 
tember. 

“A single representative for each valve will be admitted to 
witness these tests on application to the subscriber. 

“WM. BURNETT, 

“ Supervising Inspector Generali 

In answer to the above circular, the following valves were 
received at the navy yard, Washington, viz: 


SAFETY-VALVE TESTS. 


7 


G. W. Richardson, Troy, N. Y. 

G. F. Morse, Portland, Maine. 

E. H. Ashcroft, Boston, Mass.. 

G. H. Crosby, Boston, Mass.. 

Fletcher, Harrison & Co., N. Y., (Cockburn’s) 
C. H. Delamata, N. Y., (Lassoe’s). 

G. B. Sisson, Buffalo, N. Y. 

J. C. Hodgins, Toronto, Canada. 

Samuel Boden, Louisville, Ky. 

H. G. Ashton, Boston, Mass. 

F. Harden, Charleston, S. C. 

Ivinkle & Bostick, Fort Wayne, Ind. 

Union Brass Works, Chicago, Ill., (Orme’s) .. 

Walter Dawson, Scranton, Pa. 

J. D. Lynde, Philadelphia, Pa. 

Case & Baillie, Detroit, Mich. 

J. H. Blake, Boston, Mass., (Chamberlain’s) . 

Geo. H. Clemens, Chicago, Ill. 

J. T. States, Brooklyn, N. Y. 

A. B. Bell, Wilmington, Del., (Swann’s). 

W. G. Cowell, New Haven, Conn. 

H. G. Heginhothom, Philadelphia, Pa. 

J. Donfler, Milwaukee, Wis. 

Nelson Finkle & Co., N. Y. 

James Hoffman, Philadelphia, Pa .. 

J. D. West & Co., N. Y., (Rochow’s). 

E. H. Ripley, Boston, Mass. 


3 valves. 
3 “ 

2 “ 

5 “ 

2 “ 

2 “ 

2 “ 

1 “ 

2 “ . 

1 “ 

1 “ 

1 “ 

2 “ 

1 “ 

3 “ 

1 “ 

1 “ 

1 “ 

1 “ 

1 “ 

1 “ 

1 “ 

1 “ 

1 “ 

1 “ 

2 “ 

1 “ 


In all. 44 valves, 

representing all the new and improved modes of construction. 

The committee also caused to be constructed under their 
supervision, and in a superior manner, six common lever safety- 
valves, represented in the sectional drawing on page 8, with 
table of dimensions: 


Area of valves expressed in square 
inches. 

5 ". 

10". 

15 ". 

20'. 

25 ". 

© 

CO 

Diameter of opening.. 

2.525 

3.37 

4.371 

5.047 

5.642 

6.781 

Diameter of valves.. 

2.76 

3.77 

4.58 

5.28 

5.86 

6.375 

Length of lever. 

25. 

30. 

35. 

40. 

45. 

47.5 

Distance of fulcrum.. 

2.5 

3. 

3.5 

4. 

4.5 

4. 75 

Angle of valve’s face. 

45° 

45° 

45° 

45° 

45° 

45° 

Width of face. 

.15 

.15 

.12 

.17 

.17 

.15 

Length of fulcrum link. 

4.5 

4.5 

4.5 

4.5 

4.5 

4.5 





















































SAFETY-VALVE TESTS. 


LEVER SAFETY-VALVE. 



In the construction 
of these valves the 
purpose of the com¬ 
mittee was to collect 
data relative to the 
outflow of steam, un¬ 
der all pressures, from 
ten to one hundred 
pounds, and to estab¬ 
lish some correct prin¬ 
ciple by which the 
efficiency of these 
valves, as compared 
with the competing 
valve of a different 
construction could be 
determined. 

Prior to the issuing 
of the foregoing cir¬ 
cular the chairman 
of the committee was 
enabled, through the 
influence of the Hon¬ 
orable Secretary of 
the Treasury, and by 
the courtesy of the 


Honorable Secretary of the Navy, to effect arrangements for 
the proposed experiments to be made at the Navy Yard, Wash¬ 
ington, D. C., as indicated by the following correspondence: 


“Treasury Department, 

“ Washington , D. (7., July 3, 1875. 

“Sir: The Board of Supervising Inspectors qf Steam-Vessels 
at ifs annual session, held in this city, January 20, 1875, ap¬ 
pointed a committee of three members, of which the Super¬ 
vising Inspector General is chairman, to make a thorough test, 





































SAFETY-VALVE TESTS. 


9 


under steam, of every safety-valve that may be presented for 
examination. 

“In prosecuting its duties the committee require a steam- 
boiler of considerable evaporative powers, and I have the honor 
to request that one of the steam-boilers in the anchor-shop, 
equipment division of the Washington navy yard, be assigned 
to the use of said committee from the 1st to the 20th of Septem¬ 
ber, unless otherwise in use at that time, all expenses for fuel 
and necessary labor to be paid by this Department. 

“As these experimental tests will also be of great interest 
to the Navy Department, it is suggested by the committee that 
one officer under the Bureau of Steam Engineering be detailed 
at the proper time to witness the said tests. 

“Very respectfully, 

“CHAS. F. CON ANT, 

“ Acting Secretary. 


“Hon. Geo. M. Robeson, 

“ Secretary of the Navy. 11 


“ Navy Department, 

“ Washington , July 8, 1875. 

“ Sir : I have the honor to inform you, in reply to your letter 
of the 3d instant, that the necessary orders have been issued to 
Commodore T. H. Patterson, the commandant of the navy 
yard, Washington, in regard to the testing of safety-valves by 
the Committee of Supervising Inspectors of Steam-Vessels, in 
accordance with your request. 

“ Very respectfully, 

“GEO. M. ROBESON, 

“ Secretary of the Navy. 

“ Hon. Chas. F. Conant, 

“ Acting Secretary of the Treasury. 11 

At the call of the chairman, the committee convened in 
Washington on the 1st of September, 1875, and, after com¬ 
pleting arrangements, commenced the experiments on the 12th, 
with the six common lever-valves, the results of which are 
tabulated in the tables numbered 1, 2, 3, 4, and 5. 

Before commencing these experiments, one day of twelve 
hours was devoted to ascertaining the evaporative powefs of 
the boiler upon which they were to be made. 


10 


SAFETY-VALVE TESTS. 


The following are the dimensions of this boiler: 


Length... 

Diameter.. 

Grate surface... 

Heating surface. 

Grate to heating surface. 

Calorimeter. 

Calorimeter to grate surface.. 

Calorimeter to heating surface. 

Estimated weight of boiler, 18,000 pounds. 


... 18 feet. 

... 6 “ 

... 23. 6 square feet. 

... .928 “ “ 

1 to 42.2 “ 

.... 3.4 “ ‘ 

. 1 to 6. 9 “ “ 

1 to 27. 3 “ * 



The shell of this 
boiler was circular in 
form and constructed 
of iron § inch in thick¬ 
ness. It had two in¬ 
ternal furnaces 2 feet 
3 inches in diameter, 
with grates 5 feet 3 
inches in length. It 
contained 157 2-inch 
brass tubes 10 feet 
in length. The con¬ 
nection with the up¬ 
take fell below the 
lower line of the tube- 
sheet. 

The following are 
the results obtained 
from the trial of this 
boiler: 

Steam pressure 
maintained exactly at 
twenty pounds by the 
gauge; 

Grood Cumberland 
coal was used; 

Water level in boil¬ 
er maintained at same 
point during the trial; 































































































SAFETY-VALVE TESTS. 


11 


Mean temperature of feed-water, 66 degrees; 

Mean temperature of up-take, noted every hour, 373 de¬ 
grees ; lowest, 324 degrees; highest, 394 degrees; 

Water-tank measured 27 cubic feet. 

13.5 tanks, equal to 22,785.2 pounds of ynter, evaporated 
during the trial; 

I, 898+ pounds of water evaporated per hour; 

965.4+ pounds of water evaporated to one square foot of 
grate surface; 

24.55+ pounds of water evaporated to one square foot of 
heating surface; 

80.45+ pounds of water evaporated per hour to one square 
foot grate surface; 

2.04+ pounds of water evaporated per hour to one square 
foot of heating surface; 

2,187 pounds of coal, less 9 per cent., consumed during the 
trial; 

166 pounds of coal consumed per hour; 

84.32+ pounds of coal consumed to one square foot of grate 
surface; 

2.14+ pounds of coal consumed to one square foot of heat¬ 
ing surface; 

7.02+ pounds of coal consumed per hour to one square foot 
of grate surface; 

.178+ pound of coal consumed per hour to one square foot 
of heating surface; 

II. 438+ pounds of water evaporated (apparent) with the 
consumption of one pound of coal; 

10.295+ pounds of water evaporated (effective) with one 
pound of coal; 

The effective ratio is found by deducting ten per cent, from 
the apparent , for the water supposed to have been entrained 
with the escaping steam. 

Draft natural. 


12 


SAFETY-VALVE TESTS. 



The following table exhibits the rate of evaporation, as to 
time, and the coal consumed. The trial commenced at 10.30 


A. M. 


Table of the water evaporated and coal consumed daring trial of boiler. 


Tanks of 
water evap¬ 
orated. 

Weight of water. 

Time occupied in 
the evaporation 
of each tank. 

Tanks of 
water evap¬ 
orated. 

Weight of water. 

Time occupied in 
the evaporation 
of each tank. 



10. 30 A. M. 



10. 30 A. M. 

1 

1687.5 

40 minutes. 

9 

1687.5 

48 minutes. 

2 

1687. 5 

65 

do. 

10 

1687.5 

70 

do. 

3 

1687.5 

48' 

do. 

11 

1687. 5 

50 

do. 

4 

1687. 5 

52 

do. 

12 

1687.5 

54 

do. 

5 

1687.5 

50 

do. 

13 

1686. 5 

53 

do. 

6 

1687.5 

48 

do. 

itank 

847.7 

33 

do. 

7 

1687.5 

52 

do¬ 


10. 30 P. M. 



8 

1687.5 

57 

do. 









13.5 

22787.2 

720 m.=12 hrs. 


Note. —Eighteen buckets of coal =2187 pounds —197 pounds of ashes, &c., re¬ 
moved = 1990 net pounds of coal consumed. 

Mean time to each tank, 53. 33 m. = 31.67 lbs. per min. 

Mean time to each bucket, 40 m. =2. 76 lbs. per m in. 

Maximum of evaporation = 2531.25 lbs. per hour. 

Minimum of evaporation = 1446.42 lbs. per hour. 

Mean of evaporation = 1900 lbs. per hour. 


For testing these valves, a cast-iron pipe of sufficient length 
to hold the six valves at once, and of sufficient area to prevent 
any reduction from the pressure in the boiler when any one of 
the valves was being tried, was attached to the top of the boiler 
in a longitudinal position to the same. From the end of this 
pipe a smaller one carried the condensed water away; and a 
valve or gate was inserted between the pipe and the boiler for 
the purpose of shutting off the steam. 

Two very accurately adjusted steam-gauges were employed, 
one being attached to the pipe and the other to the boiler direct, 
and the difference in the pressure carefully noted. 















SAFETY-VALVE TESTS. 


13 


M 

cj 

3 

« g 

o 

d d 


5". <; *1 


10". { r > 
a' 

c3 


is". <; 


a 

cS 

s 


20 ". <( 


25". 


30' 


a 

C2 

IS 


TABLE No. 1. 


Pressure at which the valves were set. 


Results obtained. 

10 . 

20 . 

30 . 

40 . 

50 . 

60 . 

70 . 

80 . 

90 . 

100 . 

Excess rising. 

4|—11 

3£ 

2 

3 

3 

2 £ 

i 

3 

2k 

H 

Excess falling. 

6 *-lli 

5J 

2 | 

21 

3 

2 £ 

i 

3 

If 

2 

Lift of valve. 

.20 

.20 

.13 

.15 

.14 

.09 

.06 

.08 

.06 

.05 

Effective areas. 

1.171 

1.171 

.751 

.869 

.810 

.515 

.341 

.457 

.341 

.284 

Seated at. 

9i 

19 

28 k 

37£ 

47 

56 

65 k 

76 

85 

94 

Excess rising. 

2 

1 § 

1 

1 

u 

1 

2 

If 

2 

3 

4 

Excess falling. 

2 

If 

1 

1 

2 i 

3 

3 

4 


1 | 

Lift of valve. 

.19 

. 18 

.13 

.11 

.11 

.09 

. 09 

.06 

. 06 

.06 

Effective areas. 

1. 553 

1. 469 

1.054 

.889 

.889 

.725 

.725 

.481 

.481 

.481 

Seated at. 

9f 

19i 

29i 

39 

49 

58 

68 

78^ 

88k 

97 

Excess rising. 

1 

1 ft 

* 

u 

ii 


ii 

1 3 

1 

4 

1 

4 

Excess falling. 

1 

1 § 

| 

lk 

2 ? 


4 

3 



Lift of valve. 

.17 

. 12 

.08 

.08 

.08 

.05 

.05 

.04 

.04 

.03 

Effective areas. 

1. 689 

1.186 

.787 

.787 

.787 

.490 

.490 

.391 

.391 

.293 

Seated at. 

9 

18| 

29 3 

37 

47£ 

56 

66 

78 

77| 

95 

Excess rising. 

1 . 

A 

A 

1 

.1 






Excess falling. 

A 

A 

2 

3i 

3 

2\ 

3 

3 



Lift of valve. 

. 17 

. 13 

. 08 

. 09 

. 10 

.08 

. 04 

. 03 



Effective areas. 

1. 946 

1. 482 

. 907 

f. 022 

1.136 

.907 

. 452 

. 338 



Seated at. 

9 

18 k 

27 

37 

46 

57i 

67i 

77 



Excess rising. 

n 

1 

H 

H 

1 

4 

1 

2 

Is 

i 



Excess falling. 

H 

1 

3| 

2 ? 

1 ? 

2k 

2b 

3 



Lift of valve. 

. 15 

. 10 

. 09 

. 08 

. 04 

. 05 

. 04 

. 04 



Effective areas. 

1. 912 

1. 269 

1.141 

1 . 013 

. 505 

.632 

. 505 

. 505 



Seated at. 

9$ 

19± 

28 

37 

48 

57 

68 i 

78£ 



Excess rising. 

A 

A 

1 

1 

i 


1 














Excess falling. 

l 

a 

1 

2 

H 

2 

1 | 

2 

3 

3 



Lift of valve. 

.16 

. 11 

. 10 

. 06 

. 04 

. 04 

. 03 

. 02 



Effective areas. 

2. 234 

1. 530 

1. 389 

. 831 

. 553 

. 553 

. 414 

. 276 



Seated at. 

9* 

19£ 

28£ 

37 

46 

57 

70 

78f 












Notes on Table No. 1. 

Excess rising expresses the number of pounds which the valves allowed the pressure to exceed that 
at which they opened. 

Excess falling expresses the number of pounds above the excess rising, to which the pressure was 
forced by gaging the valve—usually double that of the rising excess—and then allowing the pressure 
to recede, if it would, retaining the valve at the same lift it made at the rising excess. 

Effective area expresses the opening due the lift of the valve; area, that due the diameter. 

All areas are expressed in square inches, and lifts in hundredths of an inch. The 5-inch valve would 
not blow down the falling excess below a pressure of 30 pounds until its readjustment, when it would 
blow down at 20 pounds. The remainder of the valves reduced the falling excess rapidly. 

All the valves at the falling excess, and at the pressures of 10 and 20 pounds, recorded considerable 
extra lifts and areas not noted in the table, viz: 


5-inch, at 10 lbs. lift, 

.27— 

area, 1.726; at 20 lbs. lift, 

.25— area, 

1,566. 

10 

U 

.24 . 

“ 2.113 

.21 

1.720. 

15 

U 

.23 

“ 2.306 

.17 “ 

1.689. 

20 

U 

.20 

“ 2.321 

.17 

1.964. 

25 “ 

a 

.21 

“ 2.564 

mean. 


30 

a 

.22 

“ 3.043 

.16— area, 

2.234. 









































































































14 


SAFETY-VALVE TESTS. 


The 5 and 10-inch valves, subsequent to their readjustment, recorded, in Tables Nos. 2 and 4, areas 
as follows: 

The 5-inch, at 30 pounds, .989; at 40 pounds, 1.110, and the 10-inch, at 20 pounds, 1.637; at 30 pounds, 
1.469; at 40 pounds, 1.225. 

These tests usually occupied ten minntes; but, at the pressure of 10 and 20 pounds, the 5 and 10-inch 
valves were on trial from twenty to thirty minutes each test. 

The 10 and 20-inch valves performed the best; the 10-inch under all the pressure, and the 20-inch 
from 10 to 80 pounds. 


TABLE No. 2. 


® ® 


a 

> 

O 

eg 

w 

H 




10 " <! 


Results obtained. 


Excess rising. 

Excess falling. 

Lift of valve. 

Effective areas. 

Commenced blowing 

Opened wide. 

Seated at. 


Excess rising. 

Excess falling. 

Lift of valve. 

Effective areas. 

Commenced blowing 

Opened wide. 

Seated at . 


Pressure at which valves were set. 


20. 

30. 

40. 

50. 

60. 

70. 

80. 

M 

& * 1 3i 

d 3$ 

d 1 2$ 

/ 2f 

h 3$ 



5 

5 

3$ 

4$ 

4 


.20 

.17 

.19 

.07 

.06 

.06 


.171 

.989 

1.110 

.399 

.341 

.341 


19 

29 

39 

49 

58$ 

69 


20 

30 

40 

50 

60 

70 


19-$ 

29$ 

39 

48$ 

58$ 

68 


a If 

c2 

c i 2 

e2i 

<7 If 

^1$ 

i 1$ 


2f 

2f 

2f 

2 

2 

n 

.20 

.18 

.15 

. 11 

.09 

.09 

.06 

.637 

1.469 

1.225 

.889 

.725 

.725 

.481 

19i 

29$ 

39f 

49$ 

59$ 

69$ 

79$ 

20 

30 

40 

50 

60 

70 

80 

20 

30 


50 

59f 

69$ 

79$ 


a Raised to 20| in 3 m. ; 21 in 6 m.; 21$ in 7 m. ; 21$ in 8 m.; 21$ in 9 m. ; 21$ in 10 m., when the 
pressure was at a stand. Action smooth, even, and prompt. 

b Raised to 21 in 1 m.; 21$ in 2 m. ; 22 in 3 m.; 22$ in 4 m.; 22* in 5 m.; 22$ in 6 m.; 23 in 7 m. • 234 

1 ft rn • 9.3 in Q m • 9 d in 10 m . oontinninnr A + f -^4- 


. - \ - * -~ v J AAl c/ in yj i_U. , 

in 8 m.; 23$ m 9 m.; 24 in 10 m.; continuing slowly. Action prompt and smooth. 

in 1 in.; 31s in 2 m.; 32$ in 3 m.32$ in 4 m.; 32$ in 5 m.; 33 in 6 m.; 33 in 7 m.; 33$ 


b l Raised to 31 in_, -, ^ 

in 8 m.; 33$ in 9 m.; 33$ in 10 m. Prompt. 

c Raised to 30| in 2 m.; 30$ in 3 m.; 31 in 4 m.; 31 in 5 m.; 31$ in 6 m.; 31$ in 7 m.; 31$ in 8 m. • 32 
in 9 m.; 32 in 10 m. Action prompt. 

ci Raised to 40$ in 1 m.; 41 in 2 m.; 41$ in 3 m.; 41$ in 4 m.; 41$ in 5 m.; 41$ in 6 m.; 41$ in 7 in • 
41$ in 8 m.; 41$ in 9 m.; 42 in 10 m. 

d Raised to 41$ in 1 m.; 41f in 2 m.; 42$ in 3 m.; 42$ in 4 m.; 42$ in 5 m.; 43 in 6 m.; 43$ in 7 m • 43$ 
m 8 m.; 43$ m 9 m.; 43$ in 10 m. , ” 

d\ Raised to 50$ in 1 m.; 51 in 2 m.; 51$ in 3 m. ; 52 in 4 m.; 52$ in 5 m •; 52$ in 6 m.; 52$ in 7 m. • 

52$ m 8 m.; 52$ in 9 m.; 52$ m 10 m. ’ 

e Raised to 51 in ] m.; 51$ in 2 m.; 51$ in 3 m.; 52 in 4 m.; 52 in 5 m.; 52 in 6 m.; 52 in 7 m • 52 in 

8 m.; 52$ m 9 m.; 52 in 10 m. 

/ Raised to 60$ in 1 m.; 61 in 2 m.; 61$ in 3 m.; 61| in 4 m.; 62 in 5 m.; 62 in 6 m.; 62 in 7 m.. 62$ in 
8 m. ; 62f in 9 m.; 62| m 10 m. ’ * 

q Raised to 60$ in 1 m ; 60$ in 2 m.; 60$ in 3 m.; 60$ in 4 m.; 60$ in 5 m.; 61$ in 6 m.; 61$ in 7 m. ; 
bl$ in 8 m.; bl$ in 9 m. ; 61$ in 10 m. 

u/s 1 *f 7H in™rn‘“ 7 ij'inK 2 * * * * * 8 “•i 71 3 71 in 4 m.; 71 in 5 m., 71Hn 6 m. ; 71J in 7 m., 71J 

ft Bated to 71 in,1m.; 71{ in 2 m. ; 72J in 3 in. • 73J in 5 m.; 73i in 7 m.; 73Hn 8 m.; 73i in 10 m. 

% Receded to 79$ in $ m.; raised to 80 m 1$ m. ; 80$ in 2 m. ; 81 in 3 m. ; 81$ in 4 m • 81$ in 5 m • 8U 

in 6 m.; 80J in 7 m.; 80$ in 8 m.; 81$ in 9 m.; 81$ in 10 m. * mum., in 5 m., 81* 

Note.—T he tests recorded in this table were made subsequent to the readjustment of the valves 
which readjustment consisted m bringing to a knife-edge all points of contact between valve and 

th ® V ldth °f fbeir seats. The areas obtained correspond nearly with those 
in Table No. 1. Excess rising and falling expresses the same as in Table No. 1. ^ 

















































SAFETY-VALVE TESTS. 


15 


TABLE No. 3. 

Thirty minutes test at 70 pounds pressure. 




VALVE, 5 SQUARE INCHES AREA. 


Pressure in 
boiler noted 
every minute. 

Excess. 

Lift of 
valve. 

Effective 

area. 

704 

4 




70 

. 




69£ 





69 





694 





70 i 

4 




704 

4 




71 

1 




714 

14 




7 0£ 

f 




704 

4 




704 

4 




70 





G9£ 



CO 

1—1 

lO 

j> 

70 




cC 



> a 

© 

70i 

4 


r-H 

& 

eH 

714 

14 


cS 

© 

rt 

ci 

© 

72 

2 



§ 

73 

3 




734 

34 




734 

34 




734 

34 




734 

34 




. 734 

34 




73 

3 




72£ 

2£ 




724 

24 




72f 

24 




72 

2 




72 

2 





VALVE, 10 SQUARE INCHES AREA. 

Pressure in 
boiler noted 
every minute. 

Excess. 

Lift of 
valve. 

Effective 

area. 

704 

4 




704 

4 




70 





70 





704 

4 




704 

4 




704 

4 




7 Of 

f 




7 Of 

f 




71 

l 




71 

1 




71 

1 




7Of 

f 


05 

O 

.725 

704 

4 


71 

714 

1 

14 


+=' 
r & 
a 

e3 

© 

U 

cS 

714 

714 

14 

14 



— 

cc 

© 

714 

14 




714 

14 




714 

14 




714 

, n 




714 

14 




714 

14 




71£ 

If 




7 If 

If 




72 

2 




714 

14 




714 

14 




714 

14‘ 





Note.— At the expiration of the 30 minutes, the pressure in the boiler was allowed 
to go up to 80 pounds, when the 5-inch valve reduced the pressure to 70 pounds in 34 
minutes, and the 10-inch in 3 minutes; the valve-levers being held at .13 and .09 
lifts. During these tests the fires under the boiler were forced quite hard. 











































16 


SAFETY-VALVE TESTS. 


TABLE No. 4. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

Excess. 

Lift of valve. ; 

Effective area. 

1 

Commenced 

blowing. 

Opened wide. ' 

Seated at. 

Area of valve. 

CO 

CO 

<D 

O 

X 

H 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

5 

5 

H 

a7i 

.16 

.16 

.929 

.929 

291 

291 

30 

30 

28 

28 

5 

&10 

51 

2 

.11 

.09 

.633 

.725 

69 

69 

70 

70 

68 

681 


a Raised to 33g in 4 m.; to 34| in 5 m.; to 35 in 7 m.; to 36£ in 8 m.; to 37£ in 10 m. 
b Opened promptly—raised to 70£ in 1 m.; 701 in 2 m.; 70£ in 3 m.; 71 in 4 m.; 711 in 5 m.; 71£ in 
m.; 71| in 7 m.; 71* in 8 m.; 72 in 9.; 71| in 10 m. Action very even and steady. No jar or unusual 
noise. 

Note. —The tests on the 5-inch valves were made prior to the readjustment, and the points when it 
“commenced blowing” and “opened wide” were very difficult to determine. 


o 

£2 


ft 


TABLE No. 5. 
Differential tests. 


5 SQUARE-INCH VALVE. 


c3 

> 

Ph 

© 

a 

P 

© 

pH 

0 


ft 


82 

70 

781 

711 

771 

701 

761 

70 

761 

691 

77 

711 

771 

711 

781 

711 

79 

711 

79 

711 

791 

72 


0 

*0 

0 

Ph 

bfi 

0 © 
bC 0 

0 Q. 

| W) 
o +3 

=4H 0 

O 

0 

© 

Ph 


> 1 . 


<D 

> 

o 

4h 

•H 

ft 


.06 


0 

© 

Ph 

0 

© 

> 

© 

r ® 

Stt 

ft 


.341 


® © 
00 

© “ 

Ph 0 
Ph P 
P ^P 
© a 

% ° 

© jg 

© .o 

p 2 

© -H 
® ® 
M U 


0 
• rH 

a 

^5 00 

pH © 

> 0 
® 0 

?0 "S 
© © 
+e O 

0 ~ 
w u 

© £ 
> « 
"3 4H 
t> P 


12 

7 

7 

61 

51 

5f 

61 

7 

7 

71 

7f 


10 SQUARE 



p 


. 

t 


> 

bC 




*o 

u 

<© 

bfi 

.S » 


0 

© w> 


0 

ft 2 

<£> 

P 

3 

GO 

o 

f-t 

S3 

GO 

'S a 

GO 

1 ? 

CO 

© 

a? 

ft 

£ 


82 

70 



77 

701 



761 

70 



761 

70 



, 761 

691 


^ 1.06 

76 

701 



761 

691 



761 

701 



771 




78 

711 

* 


82 

70 



791 

701 



781 

70 



781 

691 



781 

701 



781 

71 


>1.20 

80 

711 



801 

711 



811 

711 



811 

711 



811 

711 




©H 

3 


.08 


.09 


e3 

© 

pH 

0 

© 

+3 

© 

Sp 

ft 


.644 


.725 


® £ 
© *0 
© a 
Ph p 


p 

a 

00 

<V hM 

© p| 

'S 1 
o S 
© 

© ,o 

£ ^ 
0 ® 
> 0 


12 

6i 

6f 

61 

7 

5i 

7 

6i 

6i 

6i 

12 

8* 

81- 

Si 

8 

71 

81 

9 

10 

10 


















































































SAFETY-VALVE TESTS. 


17 


In conducting these experiments the committee labored 
under the disadvantage of having no well-authenticated prece¬ 
dents to assist, and, in some instances, found it necessary to 
review and correct their work. By an inspection of the tables 
an irregularity in areas obtained will be observed, which, at 
first sight, appears difficult to account for, even after allowing 
for all excess, and the difference in the rate of evaporation of 
the boiler, which was from 1,400 to 2,500 pounds per hour; 
and it was only after considerable practice in the manipulation 
of the valves that this irregularity could be explained, and, to 
some extent, corrected. 

In the operation of these valves, under pressure of steam, it 
was observed that the points at which they commenced to blow, 
(not leak,) and when they opened wide, or nearly exposed the 
areas (if the diameter of the valve would admit of such area) 
due the pressure and volume of the escaping steam, were 
very clearly defined, and, when carefully noted, a much greater 
uniformity in their v operation was the result; particularly was 
this the case with the reactionary valves, or valves whose lifts 
could be increased or decreased by manipulating some of their 
parts. 

No inconsiderable amount of this irregularity is due, no doubt, 
to the difference in the width of the seats, as well as other im¬ 
perfections existing in the valves. Some allowance should also 
be made for irregularities in supplying the boiler with fuel and 
water, though, in these particulars, great care was observed, 
and the condition of the fires in the furnace and the height of 
the water in the boiler, at the commencement of each test, 
made as near alike as possible, and no supply was allowed 
during the continuance of the test, which, as a rule, was of ten 
minutes’ duration. 

The lifts of the valves, the results of the tests of which are 
recorded in Table No. 1, were obtained in the following manner: 

The six valves were all attached to the pipe at the same time, 
2 


18 


SAFETY-VALVE TESTS. 


and their levers increased in length to twenty fulcrums, by the 
addition to each lever of a rod of light wood, with a metal 
point fixed at their extremes, and made to coincide with sta¬ 
tionary cards. The manner of operating was thus: 

Before the valves commenced to rise from their seats, a 
mark was made on the cards, by pressing, with the hand, the 
sharp metal points against them, and when the levers were at 
their extreme heights, while operating—that is, when all the 
rising excess was made, another mark was made on the cards. 
The distance between the two marks on the cards was then 
carefully measured, reduced to hundredths of inches, and 
divided by twenty. 

The effective areas of all the valves, both common and com¬ 
peting, were found by the following rules, viz: 

Rule 1. Let E A = Effective area of valve, in square inches. 

D = Diameter of valve, in inches. 

L = Lift of valve, in hundredths of an inch; then, 

E A = D + L - 2 X 3.1416 X L - . 29; 

Or, expressed in arithmetical form: 

1. To the diameter of the valve add one-half the lift. 

2. Multiply this number by 3.1416, and the last product by . 71 of the lift, for the 
effective area. 

The conditions incident to this rule are: Diameter and lift 
are given; angle of inclination of valve-seat must be 45 degrees 
to the centre line of its axis; valve must not rise out of its 
seat, or above a line perpendicular to its angle of inclination, 
and meeting the upper edge of the seat and the lower edge of 
the valve. When a valve rose above this perpendicular line 
the amount of area so obtained was found by the following rule: 

Rule 2. Multiply the diameter of the valve by the additional lift, and by 3.1416. 
Add this last product to the first, for the whole effective area. 

When the seat of the valve was flat, at an angle of inclination 
of 90 degrees to the centre line of axis, the effective area was 
found by Rule 2, leaving out the word additional and the last 
clause of the rule. 


SAFETY-VALVE TESTS. 


19 


Rule 1 is based upon the formula applied to finding the sur 
face of a frustum of a cone, the upper base of which is equal 
to the diameter of the valve, the lower base equal to the diam¬ 
eter plus the lift of the valve, and the slant height equal to .71 
of the lift. 

It will be noted in Table No. 1, that the tests on the valves 
with areas of five, ten, and fifteen square inches, were carried 
from ten to one hundred pounds pressure, varying by tens, and 
that the tests on the valves with areas of twenty, twenty-five, 
and thirty square inches, were carried from ten to eighty pounds 
pressure. 

It was found that no practical results could be obtained on 
this boiler, by going above eighty pounds with the larger valves. 
On a trial of the thirty-inch valve at one hundred pounds press¬ 
ure, it hardly rose at all from its seat, but appeared to tilt y 
alternately from one side to the other, sufficient to allow all the 
steam to escape that the boiler was capable of generating. 

It will also be noted that the lift of the thirty-inch valve, at 
a pressure of eighty pounds, was only 0.02 of an inch, with 
one pound rising excess, and that the ten-inch valve, at the 
same pressure, made a greater effective area. 

The general results obtained by the tests on the common 
lever-valve are recorded in this table. Great care was taken 
in ascertaining the exact areas exposed by each valve, under 
each pressure, as well as the excess made over that at which 
the valve opened, and the pressure at which they were seated. 
The division of the opening point of the valve into “ commenced 
blowing ” and u opened wide v are not given in this table; and the 
omission is due to the fact that the committee did not dis¬ 
tinctly observe them at the time. 

In Table No. 2, the results are recorded which were obtained 
from these valves after their readjustment, and all their connect¬ 
ing points, where the friction could be reduced, brought to 
knife-edges. These tests are more favorable to the efficiency 


20 


SAFETY-VALVE TESTS. 


of these valves than the tests recorded in Table No. 1; less 
excess is made and their action more uniform. The elements 
of these valves are best expressed in the notes attached to the 
tables. 

In Table No. 3, the results are given, obtained from tests con¬ 
tinued for thirty minutes, allowing the boiler time to exhibit all 
the phases incident to supplying the same with fuel and water. 
The valve, with an area of five square inches, made an excess 
of three pounds, and the one with an are^ of ten square inches, 
an excess of only two pounds. These were the highest excesses 
made during the continuance of the tests. The fires during 
these tests were forced quite hard. 

The data tabulated in Table No. 4 exhibits the action of 
these valves under the same conditions as to the pressure of 
steam, time, &c., as existed during the tests with the competing 
valves. 

Table No. 5 (differential tests) exhibits results obtained un¬ 
der the following conditions, viz: 

A plate or valve , accurately graduated to the thousandths of 
an inch, was placed in the pipe between the boiler and the 
valves. Prior to the commencement of a test, the pressure in 
the boiler was raised to twelve pounds above that in the pipe, 
or the pressure at which the valves were set to open, and main¬ 
tained at this pressure, as near as possible, by manipulating the 
graduated plate, so as not to allow the valve to close, nor the 
pressure to rise in the boiler. 

The pressure in both boiler and pipe was noted every minute 
for ten minutes. The areas obtained on these valves during 
the tests are nearly the same as were obtained from other tests. 
The areas obtained on the graduated plate are considerably 
larger than those on the valves. 

These areas are the maximum in all cases. 

The tendency of the two pressures to equalize will be ob¬ 
served, and it was found very difficult to maintain, near the 
the original points, their differential quantity. 


SAFETY-VALVE TESTS. 


21 


The committee are not confident that any very useful infor¬ 
mation can be derived from the results obtained by these 
differential tests. Some engineer, however, may discover in 
them some useful data, and from this consideration they are 
here presented. This remark will apply to the differential 
tests made on some of the competing valves, the table of which 
accompanies the tables of the regular tests of these valves. 

An analyzation of Tables 1, 2, 3, 4, and 5, is exhibited in 
Table No. 6, giving the maximum, minimum, and mean results. 

According to this analysis, the effective areas decrease in the 
same ratio as the pressure increases; and, taking the highest 
mean , the effective area sufficient to discharge all excess of 
steam for a boiler evaporating 1,900 (mean) pounds of water 
per hour, at a pressure per square inch of— 


10 pounds, will not exceed 1.900 square inches. 


20 

30 

40 

50 

60 

70 

80 

90 

100 


1.500 

1.200 

1.100 

.906 

.800 

.700 

.600 

.500 

.400 


The maximum areas obtained were a little in excess of the 


above, but it must be kept in mind that the boiler evaporated at 
the rate of 2,500+ pounds of water per hour some portion of 


the time ; 

Also, that the diameter of a safety-valve is not an infallible 
test of its efficiency; 

That the lift which can be obtained on a safety-valve, other 
conditions being equal, is a test of its efficiency; 

That the lift of a safety-valve depends upon the velocity and 
weight of the escaping steam; 

That the valves with small areas made a greater excess than 
those with large areas, even when the former recorded a greater 
maximum of effective area; 


22 


SAFETY-VALVE TESTS. 


That two-tenths of one inch is the maximum lift to be ob¬ 
tained on a common lever safety-valve; 

That the common lever safety-valve, when constructed upon 
correct principles, employing good material and workmanship, 
will correctly indicate the maximum pressure of steam in a 
boiler, and, when suitably proportioned, relieve the same of all 
excess. 

TABLE No. 6. 


An analyzation of Tables Nos. 1, 2, 3, 4, and 5, giving the maximum, minimum, and mean of 

results. 


Pressure, in lbs., per sq. in. j 

Aggregate of effective areas 
obtained at pressure. 

Maximum effective areas 
obtained at pressure. 

Areas of valve upon which 
maximum areas were ob¬ 
tained. 

Minimum effective areas ob¬ 
tained at pressure. 

Area of valve upon which 
minimum area was ob¬ 
tained. 

Mean of all effective areas. 

Mean of effective areas, less 
the minimum. 

Per cent, of excess of maxi¬ 
mum area. 

Per cent, of excess of mini¬ 

mum area. 

Maximum excess made at 

pressure. 

Area of valve upon which 
maximum excess was made. 

10 

10. 505 

2. 234 

30 

1.171 

5 

1. 751 — 

1. 867 

5. 

47. 5 

47.5 

5 





1.186 

15 







20 

8. 273 

1.637 

10 

1.171 

5 

1. 379 — 

1. 454 

8. 75 

20. 

20. 

5 

30 

6. 682 

1. 469 

10 

..787 

15 

1.114 — 

1.179 

6.6 

2. 5 

11.— 

5 





.831 

30 







40 

5. 988 

1. 225 

10 

.787 

15 

. 996 

1.092 

5. 

2. 8 

8. 75 

5 





.553 

30 











.505 

25 







50 

4. 680 

1.131 

20 

.399 

5 

.760 

.916 

1. 

5. 

5. 

5 





.553 

30 











. 499 

15 







60 

3. 822 

.907 

20 

.341 

5 

.637 

.755 

0 . 

5. 5 

5.5 

5 





. 414 

30 











.452 

20 







70 

3.338 

.751 

5 

.341 

5 

. 556 + 

.618 

5. 

1.4 

7.5 

5 





.391 

15 











.338 

20 







80 

2. 448 

. 505 

25 

.276 

30 

. 408 

.461 

.36 

i 0 . 

4.3 

5 

90 

1.213 

.481 

10 

.341 

5 

.404 

.434 

2.2 

2. 8 

2.8 

5 

100 

1. 058 

.481 

10 

.284 

5 

.353 

. 387 

. 75 

1. 25 

1.25 

5 


Note.— Areas are all expressed in square inches. The areas named under the head¬ 
ing “Mean of effective areas, less the minimum/’ are obtained by not including in the 
calculation the minimum named, and reducing the divisor in the same proportion. 

The aggregate of the effective areas of the same valve at all the pressures from 10 
to 80 pounds, for the 5-inch = 6. 973; 10-inch = 8. 713; 15-inch = 6. 507; 20-inch = 
8.185; 25-inch = 7. 482; 30-inch = 7. 780 square inches. 

The effective areas necessary to discharge a given weight of 
steam in a given time being known, the next step in this inves- 



































SAFETY-VALVE TESTS. 


23 


tigation is to find the effective areas for any weight of steam in 
the same time. The rule of proportion will give these areas; 
or, perhaps, the following formula will be found more conve¬ 
nient. It gives nearly the same areas as were obtained by the 
foregoing tests. 

Let A = effective area in square inches, and W = mean pounds of water evapor¬ 
ated in one hour. 

W X 0.0011. 
W X 0.0010, 
W X 0.0009. 
W X 0.0008. 
W X 0.0007. 
W X 0.0006. 
W X 0.0005. 
W X 0.0004. 
W X 0.0003. 
W X 0.0002. 

As the effective area depends upon the weight of steam to 
be discharged, it is necessary to find some practical means for 
determining the mean evaporation; and if some safe ratio can 
be established between the grate or heating surface, the amount 
of coal consumed, and the weight of water evaporated in a 
given time, also the pounds of water evaporated to the pound 
of coal, a practical formula can be given. 

By inspection it will be found that, in the case of the boiler 
employed in these tests, the water evaporated to the pound of 
coal, multiplied by the pounds of coal consumed per hour to 
the square foot of grate surface, and by the grate surface, will 
give the mean weight of water evaporated in one hour; con¬ 
sequently, for all practical purposes, the weight of the steam 
discharged, thus: 11.438 X 7.02 X 23.6 = 1,895 mean pounds 
of water evaporated per hour. But it is evident that this boiler, 
while its rate of evaporation to the pound of coal was large, its 
consumption of coal per square foot of grate surface was equally 
small, and, although an economical, is not a boiler of large 
power. 


10 pounds per square inch. A — 

20 “ “ A = 

30 “ “ A = 

40 “ “ A = 

50 “ “ .-.A = 

60 “ “ A = 

70 “ “ A = 

80 “ “ A = 

90 “ “ A = 

100 “ “ A = 












24 


SAFETY-VALVE TESTS. 


The evaporation per minute, per square foot of grate surface, 
at a pressure of twenty pounds, was only 1.34 pounds, whereas 
twice this amount in a marine boiler with a natural draft, and 
from three to four times with a forced draft, and from eight to 
six pounds of water evaporated to one pound of coal, is more 
in accord with good practice. 

With this explanation the proposed formula will be expressed 
thus: 

Let G = grate surface in square feet, and W = weight of water evaporated per 
hour. 

(1.) W = 14 X 8 X G, for natural draft. 

(2.) W = 28 X 6 X G, for forced draft. 

Applying (1) to this boiler, will give 14 X 8 X 23.6 = 2644 
pounds, the weight of water evaporated per hour. 

Referring to the foot-notes attached to the table of water 
evaporated, &c., it will be noted that the maximum evapora¬ 
tion was at the rate of 2,531+ pounds per hour. 

Apply (2), and it will give 28 X 6 X 23.6 = 3965 as the 
pounds of water to be evaporated per hour. 

If this is not considered safe in every case which may occur, 
the numbers 14 and 8 (1) and 28 and 6 (2) have only to be 
increased until safety is assured. 

It only remains, in this connection, to find the diameter or 
area of the valve that will give the effective areas required ; and 
it may be safe to assume that 0.2 of an inch is about the maxi¬ 
mum of lift to be obtained on a common lever-valve, with a flat 
or bevelled seat, at the minimum of pressure. By an examina¬ 
tion of the tables it will be found that 0.2 of an inch was all 
that any of the valves could be forced from their seats without 
a considerable increase in the pressure, equalling, in the case 
of a valve with an area of five square inches, at ten pounds 
pressure, 110 per cent, excess. To get any considerable 
increase in the lift, it is necessary to increase the pressure in a 
greater ratio than that of the lift. This is but reasonable to 
suppose when we consider that as soon as a valve begins to 


SAFETY-VALVE TESTS. 


25 


leave its seat new conditions are introduced. The high velocity 
with which the steam escapes reduces the pressure at and near 
the orifice of escape, and its dynamical effect upon the increased 
area of the valve is not that due the pressure when acting upon 
the valve at rest. Some experiments made in Scotland to test 
this point showed a reduction of near 70 per cent. Then gauges 
were applied, in as many positions, to the valve-seat, and the 
pressure noted while the discharge was taking place. 

All the six valves, with the exception of the one with an area 
of five square inches, at the pressure of ten and twenty pounds, 
afforded sufficient effective areas to discharge the weight of 
steam generated, and, by the following comparison, it will be 
found that the lifts and areas of the several valves decreased 
from the lowest to the highest pressure in nearly an exact pro¬ 
portion, the difference being less than one per cent., viz: 


5-inch, decrease of lift from 10 to 100 lbs., 75—of areas 76—per cent. 


10-inch, 

u 

“ 

10 to 100 lbs., 70- 

“ 

71— 

“ 

15-inch, 

“ 

“ 

10 to 100 lbs., 82+ 

“ 

83- 

“ 

20-inch, 

“ 

u 

10 to 80 lbs., 82+ 

u 

83- 

u 

25-inch, 

u 

“ 

10 to 80 lbs., 73+ 

“ 

74- 

“ 

30-inch, 

u 

“ 

10 to 80 lbs., 88— 

u 

88- 

“ 


It will be noted in the tables, that the valves with ten and 
twenty square inches areas, for the same range of pressure, 
give nearly the same areas, the valve with ten inches giving 
the largest, but at the same time making more excess. The 
committee is of the opinion that this extra excess is due to the 
difference in the dynamical effect of the pressure upon the two 
areas, the smaller area being affected to a greater extent, 
with a tendency to seat itself, and it will be observed that the 
ten-inch valve seated at from one to two pounds higher press¬ 
ure than the larger valves. 

In the arrangement of safety-valves for any boiler, or set of 
boilers, the committee is of the opinion that a number of 
valves (where more than one is required) is preferable to one 
valve with a large area; and do not believe it advisable to 
employ a common lever-valve, with either a bevelled or flat 


26 


SAFETY-VALVE TESTS. 


seat, of more than ten square inches area. According to the.se 
experiments, two such valves will discharge four thousand 
pounds of steam in one hour, at all pressures from 20 to 100 
pounds, and, if the results deduced from the experiments are 
taken as conclusive, the rule of proportion is all that is required 
in arranging the areas necessary to discharge the weights of 
steam generated, without any reference to its pressure. 

The following rule is the nearest approximation these tests 
will warrant, viz: 

Weight of water evaporated in one hour multiplied by 0. 005: 

Or, 

An area of 5 square inches up to 1,000 pounds, 

An area of 10 “ from 1,000 to 2,000 pounds, 

An area of 20 “ from 2,000 to 4,000 “ 

An area of 30 11 from 4,000 to 6,000 u 

An area of 40 “ from 6,000 to 8,000 u 

evaporated per hour. 

It will be interesting as well as instructive, perhaps, before 
commencing with the competing valves, to compare these re¬ 
sults with results obtained from other experiments, as well as 
with the various rules laid down by distinguished engineers for 
determining the size of a safety-valve. 

A most interesting series of experiments on safety-valves 
was made a few years since by a committee of the “Institution 
of Engineers and Ship-builders of Scotland.” A discussion had 
arisen among the Scottish and English engineers relative to the 
proper construction of a safety-valve, and the rules of the 
“English Board of Trade,” as to the areas required and the 
mode of loading these valves. 

It appears from the record that these experiments were in¬ 
stituted for the purpose of deciding the points at issue. Two 
valves only were tested—those approved by the “Board of 
Trade”—with one-half of a square inch area to one square foot 
of grate surface, and loaded with weights direct. The boiler 
upon which the experiments were made was of the tubular 
kind, with 746 square feet of heating surface .and twenty-five 
square feet of grate surface. 


SAFETY-VALVE TESTS. 


27 


The experiments were carried from five to forty-five pounds 
by the gauge, varying by five pounds, with the results as tabu¬ 
lated below: 


Pressure at which valve opened. 


Results obtained. 

5. 

10. 

15. 

20. 

25. 

30. 

35. 

40. 

45. 

Excess, (in pounds). 

9 

9 

10 

10 

u 

10 

9 

8.5 

7 

Lifts, (in inches). 

.325 

.255 

.18 

.16 

.1425 

.1262 

.1125 

.103 

.097 

Areas, (in square inches) 

3.008 

2.077 

1. 631 

1.448 

1.291 

1.135 

1.019 

.929 

.875 

Per cent, of excess. 

160. 

90. 

66. 

50. 

44. 

33. 

25.7 

21. 

15. 5 


Maximum evaporated = 5085 pounds of water per hour. 
Minimum “ = 3615 u 11 

Mean “ = 4078 “ “ 


Valve’s seats were at an angle of 45 degrees to centre of axis. 

Areas calculated by formula employed in the experiments 
made by your committee. The lifts are supposed to have been 
taken at the excess pressure. 

By adding the lifts and areas due the u falling excess ,” noted 
in Table No. 1, and allowing for the larger areas of the Scotch 
valves, it will be found that the two series of experiments very 
nearly agree as to areas obtained. 

The Scotch committee give the following formula for deter¬ 
mining the areas of valves, and recommend, when the heating 
surface of a boiler exceeds thirty feet per one foot of the grate 
surface of such a boiler, the area of the valves to be employed 
should be determined by the heating surface: 


Let A = Area of valve in square inches. 

G = Grate surface in square feet. 

HS = Heating surface in square feet. 

P = Absolute pressure in pounds per square inch. 


Then, 


A=li^ ; or,A=«^iL S . 


This formula is for valves of the ordinary construction; but 
when valves are to be employed, the lifts of which can be 
made to equal one-quarter of their diameter, 






















28 


SAFETY-VALVE TESTS. 


Or, 


4 X Gr 

A should = - - " Area of valve-guide 

A .133 X H S , . - i ., 

A = - p - + Area of valve-guide. 




If the ordinary valve is employed, 

The area should be for 20 lbs., absolute, 45. square inches. 


u 

u 

25 

U 

u 

36. 

u 

u 

li 

30 

U • 

a 

30. 

u 

a 

li 

35 

u 

u 

25.7 

u 

a 

u 

40 

u 

u 

22.5 

u 

u 

u 

45 

u 

u 

20. 

u 

u 

u 

50 

u 

u 

18. 

u 

u 

u 

55 

u 

u 

16. 36 

u 

u 

u 

60 

u 

u 

15. 

u 

u 

li 

65 

u 

u 

13. 84 

u 

u 

u 

70 

. u 

u 

13. 

u 

u 

u 

75 

u 

u 

12. 

u 


Absolute pressure — pressure by gauge + mean atmospheric. 

The committee assert that the lifts of the valve recom¬ 


mended will in all cases be equal to their diameters divided by 
the constant, 36 . 

By applying the rule deduced from Professor Rankin’s ex¬ 
periments “ to the highest evaporative power of the boiler upon 
which the tests were made by your committee, the following 
are the results obtained, viz: 


"Weight discharged per 
Pressure. Absolute pressure. hour to 1 square inch 

of opening. 


10 + 14. 7 = 24. 7 pounds = 1270. 321 pounds = 


20 + 14. 7 = 

34.7 

u 

30 + 14.7 = 

44.7 

u 

40 + 14. 7 = 

54.7 

u 

50 + 14. 7 = 

64.7 

u 

60 + 14. 7 = 

74.7 

u 

70 + 14. 7 = 

84.7 

u 

80 + 14. 7 = 

94.7 

u 

90 + 14. 7 = 

104.7 

u 

100 + 14. 7 = 

114.7 

u 


= 1784.621 

u 

= 

= 2298.921 

u 

= 

= 2813.221 

u 

= 

= 3327.521 

u 

= 

= 3841.821 

u 

= 

= 4356.121 

u 

= 

= 4870.421 

u 

= 

= 5384.721 

u 

= 

= 5899.021 

a 

— 


At maximum pressure, according to 
these tests. 

1. 968 square-inch effective area. 


1.400 

u 

u 

1.087 

u 

u 

0. 888 

li 

u 

0. 781 

u 

u 

0. 677 

u 

u 

0. 570 

a 

ll 

0. 513 

u 

u 

0. 464 

u 

u 

0. 423 

u 

u 


a rfZu?^c e ? m6ntS ° f 1>r ° fessor Tlankin P rov ? th at the weight of steam which would flow through 
an orifice of one square inch area in one second of time, was just equal to one-seventieth (1-70) of the 
1 tw U £ pre f ure of the steam This was subsequently confirmed by other experimenters ? 

The formula deduced from these experiments, as applied to these tests, can be stated thus- 
-Let A 1 = Absolute pressure of the steam; 

Wl = Weight of steam discharged per hour to the square inch- 
Then, W2 = Weight of water (maximum) evaporated per hour, according to these tests. 

. W 2 

A P X 51. 43 = W 1 and Effective area of valve; 

Or, 


A P X 60 70 = W 1 and 


W 2 

WT 


= Effective area of valvi 









SAFETY-VALVE TESTS. 


29 


The following rules for determining the requisite area for a 
safety-valve, applied to this hoiler, will give: 


Heating surface 
25 


For the Buie of United States Board of Supervisors. 

= 37 square inches area of valves. 

English Board of Trade Buie. 

Grate surface < 

2 = 11.8 square inches area of valve. 

French Buie. 

Grate surface + 22.5 = 531.00 „ . „ 

Heating surface X 8.62 = im = 6/75 s< l" are luches area of valve ' 

Molsworth’s Buie. 

Grate surface X .8 = 18.88 square inches area of valve. 


Professor Thurston’s Buie. 
(1.) Coal consumed per hour X 4 = 664. 

Pressure + 10 = 80 


8.3 square inches area of valve. 


u 

u 

u 


(2.) Heating surface X 5 = 4640 . „ , 

v ' m xx o — 7777 . = 29 square inches area of valve. 

Pressure X 10 X 2 = 160 1 

Professor Bankin’s Buie. 

Weight of water evaporated in one hour X 0.006 = 12 square inches area of valve. 

Committee’s Buie. 

Weight of water evaporated in one hour X 0.005 = 10 square inches area of valve; or, 
5 square inches area of valve for boiler evaporating up to 1,000 pounds per hour. 

10 “ “ “ from 1,000 to 2,000 pounds per hour. 

20 u u u from 2,000 to 4,000 “ 

30 “ ‘‘ “ from 4,000 to 6,000 u 

40 « « “ from 6,000 to 8,000 “ 

Committee’s rule for ascertaining the weight of water evap¬ 
orated per hour is stated as follows, viz: 

Grate surface X 14 X 8 X 0.005 = weight of water evaporated per hour with natural 
draft. 

Grate surface X 28 X 6 X 0.005 = weight of water evaporated per hour with forced 
draft. 

There are several other rules based upon the nominal horse¬ 
power of an engine, given by Bourne, Byrne, and others, but 
these rules are not much in use. 

COMPETING VALVES. 

In commencing the experiments with the competing valves, 
it was decided by the committee that the same conditions as 







30 


SAFETY-VALVE TESTS. 


to the boiler, as existed in the experiments with the common 
lever-valve, should be carefully observed; that the valves should 
be tested at thirty and seventy pounds pressure only; that a 
test should be considered as continuing ten minutes, and should 
be repeated until all the parties interested should express them¬ 
selves as satisfied with the trial. 

The persons representing these valves were allowed to adjust 
them to the pressures; supply any deficiency found to exist, 
and were required to inform the committee when ready for a 
test. This course of proceeding occasioned delay, but was 
considered as the best to be pursued. 

In most instances these competing valves required readjust¬ 
ment for the pressure and volume of steam supplied, although 
they were supposed to have been put in the most perfect work¬ 
ing order possible prior to their being presented. The condi¬ 
tions under which the valves were first adjusted and those 
existing when they were put to competitive trial probably were 
not the same. In the first instance, a majority of these valves 
were adjusted to boilers which furnished but a small volume of 
steam, entirely inadequate to prove their efficiency or capacity, 
but when the competitive tests were made a volume of steam 
was furnished to the full extent, in most instances, of the capac¬ 
ity of the valves, and, in some cases, a volume far beyond that 
which they were able to control. 

As the construction of these valves in most instances pre¬ 
vented the application of the same means for ascertaining their 
lifts, as were applied to the common lever-valves, the commit¬ 
tee had constructed an apparatus arranged so as to be readily 
applied and operated by the upward movement of the valve- 
spindle. This apparatus registered, upon a dial, the thou¬ 
sandths of an inch. During these tests the consumption of coal 
and water was in the proportion of about 188 pounds of the 
former to 1,900 pounds of the latter. 

These competing valves may be classified as - follows, viz: 




SAFETY-VALVE TESTS. 


31 


Reactionary Safety-valves. 

The construction of which is such that the steam, after pass¬ 
ing the ground-seat of the valve, and prior to its final exit into 
the atmosphere, is opposed by a stricture , so to speak, which 
stricture generally consists of an extension of the valve beyond 
the ground-seat and curved downwards, but in some instances is 
either straight or bevelled, and a corresponding extension of 
the casing curved upwards. 

Dish Safety-valves. 

Valves constructed with disks attached to their spindles, 
either below or above their ground-seats. These disks are of 
larger areas than the areas of the valve proper, and when at¬ 
tached to the spindles below the ground-seats operate in a 
recess, which may be termed a reduction chamber. 

Annular Safety-valves , 

Constructed with two ground-seats upon an annular opening 
and allowed an external and internal escape for the steam. 
Some of these annular valves have attached to the valve or 
casing an adjustable lip for the purpose of controlling the exit 
of the steam. 

Double-seated Safety-valves. 

Valves constructed with two openings of unequal areas for 
the escape of the steam. The valves are attached to the same 
spindle, and the pressure acting upon the one with the larger 
area tends to force it from its seat; the pressure acting upon 
the one with the small area tends to force it to its seat. The 
extra force applied to prevent the valve from opening is just 
sufficient to balance the difference between the two areas. 

Combination Safety-valves. 

Under this classification are placed such instruments as are 
assisted in their operation through the intervention of small 
auxiliary valves or a combination of levers. 


32 


SAFETY-VALVE TESTS. 


Piston Safety-valves. 

Instruments operated by the pressure of the steam acting 
against the end of a piston fitted to a cylinder, forcing it 
outwards, and disclosing gradually the opening to the valve. 

The object sought to be obtained by the principle in¬ 
volved in the reactionary-valves, is to force the valve further 
from its seat, and thereby obtain a larger area than that, pri¬ 
marily, due to the pressure and volume of the escaping steam 
when acting only upon the area due to the diameter of the 
valve. It is quite evident that if the steam, after passing the 
ground-seat of a safety-valve, and before it can make its final 
exit into the atmosphere, is opposed by any means which will 
act to retard its escape, and force it against the valve-seat and 
any overhanging portion of the valve, will have a tendency to 
force the valve further from its seat than it would if left free. 
It is equally evident, however, and these tests warrant the 
committee in making this statement, that such valves must 
expose a larger area than valves when the steam passes unob¬ 
structed by such means direct from their ground-seats to the 
atmosphere in order to discharge the same volume of steam. 
Some of these reactionary-valves proved very efficient, but the 
committee are not quite sure that they will prove to be the 
best in a long run. It appears to the committee that the 
nicety of the adjustment of parts required by the sharp lines of 
the stricture, as well as the fact that no one valve can be ad¬ 
justed to more than one pressure, at least within a very narrow 
limit of pressure, without extra springs, will cause them more 
frequently to get out of order than the common lever-valve, or 
some of the disk-valves. 

The action of this construction of safety-valve under pressure 
may be described, in general terms, as erratic , tremulous, and, 
in some instances, tumultuous. It was very difficult to adjust 
some of these valves twice alike, or to make them constant in 
their action, and they would not always give tHe same result 
under the same adjustment. 



SAFETY-VALVE TESTS. 


33 


Upon locomotive and the boilers of steamers navigating 
rough waters, some of these valves, no doubt, are very efficient 
instruments, and the committee have no hesitancy in recom¬ 
mending them as such, and would particularly note the Ash¬ 
croft, Crosby, and Richardson valves as the most efficient. 

Through the use of the Dish the same object is sought to 
be obtained as by means of the reactionary principle. The 
disk is usually located below the ground-seat of the valve, 
between which and the disk there is a space which may be 
designated as a reduction chamber, for the reason that when 
the valve proper is forced from its seat by the pressure in the 
boiler, the pressure in this chamber is reduced, thereby allow¬ 
ing a greater force to act against the lower and inner face of 
the disk (which is of a greater area than that of the valve 
proper) than that acting between the valve proper and the disk, 
forcing the valve further from its seat. 

A few of this construction of safety-valves produced excel¬ 
lent results, and the committee cannot refrain from mentioning 
the “Cockbourne” as exhibiting the highest efficiency. The 
“Lynde valve” also produced good results. The committee do 
not believe, however, that with the disk attached to the spindle 
above the ground-seat, as efficient a valve will be produced as 
when the disk is placed below the ground-seat and in a reduc¬ 
tion chamber. 

The principle involved in the Annular valve is not new, and 
the object sought by this construction—an increase of area— 
the committee do not believe is obtained, though free to accord 
to some of these valves merit, and would particularly name the 
u Morse” as a very efficient safety-valve. 

The double-seated valves the committee do not believe will 
ever be made to answer the purpose intended, and can say 
nothing favorable of any of this construction which were tested. 

The combination valves embrace in their construction several 
very interesting and novel features, exhibiting in the inventors 
3 


34 


SAFETY-VALVE TESTS. 


of these instruments, great skill, as well as a just comprehension 
of the requirements necessary to constitute a good safety-valve. 
The committee believe that the several attempts made in these 
valves to obtain an effective area equal to that due to the diameter 
of the opening of the valve, worthy of further effort, and would 
therefore advise these inventors not to despair of success, but to 
continue their efforts to perfect their instruments. In the pres¬ 
ent condition of these improvements, however, the committee 
do not consider it prudent to recommend any of this construc¬ 
tion of safety-valves for use on the boilers of steam-vessels. 

In the case of the piston-valves, the one irrefragable objection 
to their use remains, and the committee do not consider that in 
any of the valves of this construction, presented for test, is this 
objection removed. The fear that the pistons of these valves 
will become so clogged by the accretion of matter around them, 
unless in constant operation, as to prevent them from operating 
until a large excess of pressure is attained, condemns their 
general use. There is no doubt but that in this form of valve 
a much larger effective area can be obtained than with the com¬ 
mon lever-valve, and one with a smaller diameter may be em¬ 
ployed. 

In the trial of this form of valve the “Rochow” proved very 
efficient, and should the objection noted be removed, would no 
doubt become a very popular safety-valve. 

Following are the drawings, alphabetically arranged, illus¬ 
trating the most important features in these competing valves, 
with a short explanation, tables of the tests made, references 
and notes attached to each, and at the close a table analyzing 
the results obtained. In these references, every change of 
pressure and the peculiarities exhibited are noted, and from 
these notes the elements of these valves can best be learned. 
It will be observed that the difference in pressure, between the 
opening and closing points, in most cases, is nearly a constant 
quantity. 


SAFETY-VALVE TESTS. 


35 


No results worthy of record were obtained from the valves 
submitted by James Hoffman, Philadelphia; A. B. Bell, Wil¬ 
mington, Del.; E. H. Bipley, Boston, Mass.; and W. Gf. Cowell, 
New Haven, Conn.; and no drawings are given. 


ASHCROFT’S, (REACTIONARY,) SPRING-LOADED. 








































































36 


SAFETY-VALVE TESTS. 


Area of opening, 5 square inches; angle of valve-seat, 45 
degrees to the centre line of its axis. 

The reaction is obtained by means of the steam being made 
to escape through an extended and downward curved lip, and 
a recess in the main casing under this lip checking its flow, 
and causing the valve to lift higher, thereby exposing a greater 
area than it otherwise would. 

The seat of this valve is made of nickel, and the steam 
escapes to the atmosphere through holes in a partition in the 
recess under the valve-seat, and is made to turn upwards. 

No excess was obtained at seventy pounds pressure, the only 
pressure at which it was tested. 

Area exposed, 1.231 square inches; lift, .21 inches; closing of 
itself several times during the ten minutes trial, at from 65 J 
to 67J pounds. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

© 

> 

"cS 

t> 

o 

5 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 








a 5 


.21 

1.231 

69 

70 

65i 








b 5 



67 

70 

67* 













a Closed itself at 65J, five times during the trial. 

b Receded to 67£ in | m., and closed 67£ in 2 m.; 67J in m.; 67* in 5 m.; 67J in 6| m.; 67£ in 8 m. ; 
67£ in 9f m. Action steady. No vibrating or tremulous motion. This valve leaked considerably 
prior to its reaching the “ commenced-blowing ” point. 

























SAFETY-VALVE TESTS. 


37 



ASHTON’S (REACTIONARY) SPRING-LOADED SAFETY-VALVE. 


Area, 5 square inches; angle 
of valve-seat, 45 degrees to the 
centre line of axis. Failed at 
thirty pounds pressure to give 
any results worth recording— 
spring too rigid. At a pressure 
of seventy pounds made an ex¬ 
cess of seven pounds in five 
minutes, when the trial ceased, 
excess increasing fast. Closed 
at 68 \ pounds. 

No area recorded. 



BORDEN’S, (COMBINATION,) SPRING-LOADED. 

Area of opening, 7 square inches; angle of valve-seat, 45 
degrees. The object said to be attained by this peculiar 
combination of arrangement of a safety-valve, is the protection 
of a steam-boiler from an assumed danger which the inventor 
















































38 


SAFETY-VALVE TESTS. 


BORDEN’S, (COMBINATION,) SPRING-LOADED. 








\^MW/Mim 


Hi 

-c 

a 


p 

2 


,pf 




if 




HHHI g"——r 





r** 




M 


asserts is the case in all steam-boilers just prior to tbeir being 
in condition to explode, viz: 

That a vacuum is by some means suddenly ' created just at 
this moment, and by having a valve of a large area, arranged so 
as to open inwardly by the pressure of the surrounding atmos¬ 
phere, this danger can be averted, and an explosion prevented. 










































































































SAFETY-VALVE TESTS. 


39 


The drawing here given represents two methods by which 
this result is to be obtained. One is a common valve opening 
inwardly, located directly below and in the same casing as the 
valve proper; the other is operated by means of a large 
diaphragm upon which the pressure of the steam acts and as¬ 
sists the atmosphere in opening the valve into the boiler. 

The steam is admitted to this diaphragm through a small 
auxiliary valve, which can be set at any desired pressure. It 
was not possible for the committee to put to test the assump¬ 
tions of the inventor. 

The excess obtained on the valve proper attached to this 
instrument, at thirty pounds pressure in two trials, was 2 
pounds; at seventy pounds, the two first trials, from 1 to 4 
pounds; the two last trials no excess was obtained. 

Areas exposed at thirty pounds pressure, 1.110 square inches; 
lift, .19 inch. At seventy pounds, .574 square inch; lift, .10 
inch. Valve closed at 17, 26, 60, and 67 pounds. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

1 

8 

Lift of valve, j 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 






25 to 


7 

bl 

.10 

.574 

29-* 

70 

63 

a 7 

.... 

.19 

1.110 

251 

30 


7 

di 



68 

70 

67-* 

c 7 

2 



29 

30 

26 

7 

e 



65 

70 

62-* 







7 

f 



64 

69 

60 


a Receded to 27* in 1 m.; 26* in 4 m.; 25* in 6 m.; 25 in 10 m. Action very erratic—points very dif¬ 
ficult to define. 

6 Receded to 68 in 1 m.; 67J in 2 m.; 67* in 3 m.; 67| in 4 m.; raised to 68* in 5 m.; 69* in 6 m.; 69| 
in 7 m.; 70* in 8 m.; 70J in 9 m.; 71 in 10 m. 
c Trial of 2 m. only; spring too powerful for 30 pounds pressure. 

d Raised to 71* in 1 m.; 72 in 2 m.; 73 in 3 m.; 73* in 4 m.; 73* in 5 m.; 73* in 6 m.; 73* in 7 m.; 73* 
in 8 m.; 74 in 9 m.; 74 in 10 m. Opening and closing points not clear; action steady. 

e Receded to 64 in 1 m.; 63 in 2 m.; closing. Opened at 70 in 3* m., receding to 62*, and closed in 5 
m. Opened at 70 in 6 in.; receded to 62* in 7 m. Opened at 69* in 9 m., and closed at 69* in 10 m., 
witti steady action. 

/ Collapse valve; action very irregular and uncertain. 

































40 


SAFETY-VALVE TESTS. 



HODGIN’S, (REACTIONARY,) LOADED BY LEVER AND WEIGHT. 


Area, 5 square inches, flat and conical seat. Has an ex¬ 
tended conical-shaped lip on the valve, between which and the 
recess formed by the conical shape of the lip the steam reacts 
and assists to lift the valve from its seat. 

Excess obtained on this valve at thirty pounds pressure, first 
trial, was 6 pounds; second trial, no excess. 

At seventy pounds pressure, no excess recorded. 

Lift at thirty pounds, 37 inches; at seventy pounds, 18 inches. 

Areas exposed at thirty pounds, 2.934 square inches; at sev¬ 
enty pounds, 1.427 square inches. 

Closed when set at thirty, at 24| and 26 pounds; when set 
at seventy, at 55 \ and 56 pounds. 





















































































SAFETY-VALVE TESTS. 


41 


That the form of the stricture in this valve greatly retarded 
the outflow of the steam, is evident from the large areas obtained. 
No allowance was made for the angle of the secondary seat in 
calculating the effective areas of this valve. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

A rea of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

i 

& 5 

5 

6 

.37 

.37 

2. 934 

2. 934 

25 

25i 

30 

30 

26 

20 i 

a 5 

5 

.... 

.18 

.18 

1.427 

1.427 

65 

65 

70 

70 

56 

55-$ 


a First Trial .—Receded to 64J in 1 m.; 64 in 2 m.; 63 in 3 m.; 63 in 4 m.; 63f in 5 m.; 64J in 6 m. • 
64i in 7 m.; 65 in 8 m.; 65* in 9 m.; 65£ in 10 m.; without the aid of the spring. Action steady. 

Second Trial. —Receded to 64 in 1 m.; 62 in 2 m.; 61J in 3 in.; 61 in 4 m.; 60$ in 5 m.; 60£ in 6 in. ; 
60£ in 7 m.; 60$ in 8 m.; 61* in 9 m.; 611 in 10 m.; with the aid of spring. Action steady. 

b First Trial— Raised to 30? in 1 m.; 31$ in 2 m.; 32 in 3 m.; 32$ in 4 m.; 33$ in 5 m.; 34 in 6 m .; 35 
in 7 m.; 35$ in 8 m.; 36 in 9 m.; 35| in 10 m. 

Second Trial .—Receded to 29 in 1 m.; 28$ in 2 m.; 28$ in 3 m.; 28* in 4 m.; 28* in 6 m.; 28 in 7 m.; 
27| in 9 m.; 27$ in 10 m. 

First trial with, and second trial without spring. 


COCKBURN’S, (DISK,) SPRING AND LEVER-LOADED. 







































































42 


SAFETY-VALVE TESTS. 


Area of valve opening, 5 square inches, flat-faced; the disk 
attached to and below the valve proper. 

The valve proper is constructed in the usual manner, with 
feather-edged wings or guides extending into the casing. These 
guides extend some distance below the point where they come 
into contact with the casing, for the purpose of receiving and 
sustaining the disk. The disk is of a considerable larger area 
than that of the valve proper, and nearly fills the lower opening 
in the casing. The edge of this disk is bevelled. Below the 
casing, carrying the seat of the valve proper, and above the 
disk, is a chamber of considerable area in extent. 

The result of this arrangement is, that the steam, in its pas¬ 
sage through the narrow space between the disk and the casing 
below the valve proper, becomes wire-drawn, thereby diminish¬ 
ing the pressure in the chamber, and upon the upper side of 
the disk, consequently the under side of the disk, being ex¬ 
posed to the greater pressure in the boiler, is forced upwards, 
and a greater lift is thereby given to the valve proper than that 
due to the pressure and volume of steam in the boiler. 

The thickness of the edge of this disk, as well as its form, 
has much to do with the action of the valve. 

This valve is very simple and durable in its construction, and 
the efficiency exhibited on its trial entitled it to special attention. 

No excess was obtained at thirty and thirty-five pounds press¬ 
ure. 

Lift, .23 inch; area, 1.82 square inches. The valve tested at 
thirty-five pounds was spring-loaded. 

The excess obtained at seventy pounds pressure, J pound. 

Lift, .15 inch; area, 1.18 square inches. This valve was 
loaded by lever and weight. 


SAFETY-VALVE TESTS 


43 


Trial Tests. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

• 

Seated at. 

1 

a 5 

.... 

.23 

1.820 

29$; 

30 

27^ 

& 5 

$. 

.15 

1.180 

69 

70$; 

67f 

d5 

.... 

.23 

1.820 

28 

30 

27 

c 5 


. 15 

1.180 

69 

70$; 

68 $- 

e5 




33$; 

35 

32i 






• 


5 




33$; 

35 

32i 





















a Receded to 27$ in 2 m.; 28 in 5 m.; 28$ in 7 m.; continued to end of trial at this point. 

b Commenced blowing light at 69; opened wide at 70$; opening and closing at those points 12 times 
in the trial of 10 m. 

c. Second Trial .—Opened wide at 70$, closed at 68$. Opened and closed once every $ m. during the 
trial of 10 m. 

d Receded to 28$ in 1 m.; closing at this point 5 times, then receding to 27$; continuing at this point 
until closed at 27. 

e Valve set at 35 by agent. Lift could not be ascertained, valve being locked up by the owner. 


Differential Tests. 


© 


© 

H 

© 

x 

p 

m 

S4 


73 

74 


© 

> 

> 

u 

© 

*0 

0 

0 

© 

- 

0 


© 

Ph 


a68-$ 

68i 


CS 

U 

bJD 

•2 ® 

be 

.9 ft 

0 be 

® a 

Pi -p 

o -e 


o 

e3 

© 

u 

-4 



3 


Mean. 

23 


c3 

© 

> 

•pH 

O 

w 


Mean. 

1.820 


• u 

© 

to JZ. 
© ^ 
S P 
Pi 0 
P 13 


a 

^ CO 
P-) <£) 
CD 43 

> pi 

® .9 

q 

<£> M 

OS 

© t® 

> 

r-. © 

c3 

t> p 


4* 

5* 


© 

p 


© 

© 

Ph 


71 

71 


© 

> 

7s 

p 

© 

H© 

P 


© 

© 

P 


68i 


'T© 

e3 

H 

be 


be p 
p ^ 


Pi 

be 

.9 

S3 


=© P 


© 



Mean. 

23 


© 

»rH 

-U 

© 

.© 

PI 


Mean. 

1.820 


2 © ci 


^ P 
P P 


© q 

£ 2 

® A 

II 

p p 


to 

© 

© 

> 0 
® 0 

'g a 
-s® 
a t 
£ <2 
p-3 © 

S3 ©s 
> 0 


3i 

3i 


a This valve too large for this pressure and boiler, although its action was very even and steady. 
It was not possible to keep it blowing off; would seat itself every few seconds. 



















































44 


SAFETY-VALVE TESTS. 


CROSBY’S, (REACTIONARY,) SPRING-LOADED. 

Five square inches area of opening, with a centre discharge. 
Angle of outer seat, 45 degrees; inner seat flat. Steam dis¬ 
charges through top of casing from outer seat, and through the 
main casing of the valve below the seat from the centre opening 
or seat. 

The outward openings from the centre discharge can be 
regulated by means of an adjustable ring located upon the 
outside of the valve casing. By means of this 
ring the steam has a reactionary effect upon the 
valve, regulating its lift and area, and controll¬ 
ing, it is claimed, the pressure at which the 
valve will open within a limited range. 

By means of this central seat and discharge 
a greater area is obtained for the pressure to 
act upon as soon as the valve begins to rise 
from its seat. 

Excess obtained on this valve at thirty pounds 
pressure was from 2J to 5£ pounds; at seventy 
pounds pressure, from 3 to 5 pounds. 

Areas exposed at thirty pounds, 1.257 square inches; lift, .12 
inch; at seventy pounds, .729 square inch; lift, .07 inch. 

These excesses were only temporary, and upon a trial after 
readjustment no excess was obtained, but the range of pressure 
between the opening and closing points were about the same 
on all the trials; that is, if the valve made less excess, or none 
at all, it seated at a lower pressure. 











45 


HAEETY-VAEVE TESTS. 


Trial Tests. 


30 1‘OUNDH PRESSURE. 

70 POUNDS PRESSURE. 

> 

O 

© 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

© 

n 

P 

© 

1 

O 

05 

3 

W 

1 

© 

> 

% 

< 

| 

© 

M 

w 

Lift of valve. 

S 

I- 

05 

© 

© 

© . 

3 .2 

5 ^ 

O 

© 

£ 

Ml 

O 

Seated at. 

a 5 

3 

. 12 

1.257 

29 

30 

fc27i 

c5 

3 

.07 

.729 

69 

701 

66 

5 

41 



29 

30 

29 

5 

5 

.06 

.628 

69 

70 

681 

/o 

5i 



29 

30 

28i 

5 

4 



68f 

70 

661 










0 

5 



29 

30 

261 

5 




69 

70 

64 

5 




29 

30 

291 

e 10 




68 

70 

674 






d 2 10 




68 

69f 

U/ 4 

671 








2 5 




681 

70 

671 


















10 




69 

70 

68 













a All the steam blew off at this excess. 
b Movement of opening and closing clear and well defined. 
c Points of opening and closing very clear. 

d 1 Keceded to 661 oscillating between 665 and 67 1 during the trial. 

e First Trial .—Opened prompt, receding to 67 f, and closed in 1 m.; opened and continued at 67 f 

during trial. 

Second Trial .—Opened promptly at 69|, receded to 67£. and closed in 1 m.; opened and receded to 67J 
in 2 m.; 67; in 3 m.; 67£ in 5 m.; 61} in 10 m.; action very steady; closing promptly. 

/ First Trial .—Receded to 29£ in 1 m.; raised to 30 in 1£; 301 in 2 m.; 31 in 3 m.; *31f in 4 m.; 32} in 

5 m.; 33 in 6 m.; 331 in 7 m.; 34 in 8 m.; 34f in 9 m.; 35; in 10 m.; continuing. 

Second Trial .—Receded to 29 in 1 m.; raised to 291 in 2 m. ; 30 in 3 m.; 301 in 4 m.; 31 in 5 m.; 32 in 

6 m.; 33 in 7 m.; 331 in 8 m.; 341 in 9 m,; 35 in 10 m.; continuing very slow. 

Third Trial .—Receded to 29, and raised to 321 in 10 m. 

<7 Receded to 67 J in 1} m. ; 671 in 4 m. ; and closed at 68 in 6 m. ; 68| m. in 8 m: 68| in 10 m. ; action 
steady; readjusted. 

d* Receded to 68£ in 1 m.; 685 in 2 m.; 68; in 3 m.; 63 ; in 4 m.; 68 in 5 m.; 68 in 6 m., and closed; 
68 J in 7 m.; 68; in 9 m.; 68; in 10 m.; action steady. 


Differential Tests.—Area of Valve, 5 square inches. 


82 * 

70 

761 

65 

76 

65 

751 

65 

751 

65 

751 

65 


a 

n3 

C8 

Ch 

b£ 

s ® 

.3 ~ 

© — 

0 ■§ 
S-l W 

o 

e3 


Mean. 


)• a .1.19 


Mean. 


,© 

3 = 

W 


s: © m 

© 'S a 
a -a fej © 

© — © -M 

© 3 > = 

^ r © s 


© - % •- 


2 a > a 


Mean. 


729 



r 12 

76 

66 


Hi 

76f 

67 


11 

77 

67 

N 

101 

77 

671 


101 

771 

671 


104 







bC 

bC £ 

i a 

a. 

oS 


Mean. Mean. 


V1.19 .07 


? - - 


I ® 

1 a 


I 

5- © 

© -M 
> 2 
© - 


© -2 
-2 © 


Mean. 


.729 U 


10 

9f 

10 

9f 

10 


a Action in no way different from former trials. Area obtained by manipulating the graduating 
plate until the pressure remained standing in both pipe and boiler, with valve discharging freely. 

































































46 


SAFETY-VALVE TESTS. 


CHAMBERLAIN’S, (REACTIONARY.) 

Area of valve- 
opening, 5 square 
inches; flat seat, 
with the annular 
opening from the 
boiler tapering in¬ 
ward where it comes 
in contact with the 
conical form of the 
valve proper. 

It is claimed that 
by this form of a 
valve the effect of 
(what the inventor 
is pleased to call) the “pneumatic paradox” is neutralized; 
which phenomenon, he asserts, is exhibited in the action of a 
safety-valve. How far this may be true, or this form of valve 
obviate any difficulty of this kind, if it exists, must be left to 
the judgment of others to decide. 

The excess obtained on this valve at thirty pounds pressure 
was from 6| to 7 pounds; at seventy pounds pressure, 9^ 
pounds. 

Areas at thirty pounds, 1.58 square inches; at seventy pounds, 
.92 square inch. 

Lifts at thirty pounds, .25 inch; at seventy pounds, .13 inch. 

On one trial at thirty pounds pressure the area obtained was 
only .55 square inch; lift, .08 inch. 



30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

j Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

«5 

&5 

6f 

7 

.25 

.08 

1.580 

29 

27i 

30 

30 

28 

28 

c5 

9* 

.13 

.920 

68 

70 

67| 
































































SAFETY-VALVE TESTS. 


47 


(Notes to preceding Table, page 46.) 

a Raised to 33 in 3 m.; 34 in 6 m.; 35J in 7 m.; 36 in 9 m.; 36* in 10 m., continuing to rise. Action 
of valve sluggish. 

& Raised to 32 in 1 m.; 33 in 2 m.; 34 in 4 m.; 35 in 5 m.; 36 in 7 m.; 37 in 10 m., continuing slow. 
Opening and closing points not clear. Action very slow. 

c Raised to 72 in 1 m.; 73 in 2 m.; 75 in 3 m.; 76£ in 4 m.; 77 in 5£ m.; 78 in 7 m.; 78£ in 8 m.; 79£ in 
10 m. Action same as trial under 30 pounds pressure. The peculiar form of this valve, no doubt, 
greatly obstructed the flow of the steam. 


DONFLER’S (REACTIONARY) SAFETY-VALVE, LOADED WITH FOUR 

SPRINGS. 



Area, 5 square inches; seat, flat. This valve could not be 
nade to operate satisfactorily, at either thirty or seventy pounds 
tressure, consequently no results were obtained. 

















































































48 


SAFETY-VALVE TESTS. 


CLEMENS’S, (COMBINATION,) SPRING AND STEAM-LOADED. 



Area of valve-opening, 5 square inches ; angle of seat, 45 
degrees. The reaction is obtained by means of an enlarged 
piston or disk, attached to and above the valve proper, both of 
which are acted upon by the pressure direct, the valve proper 
upon its upper side, and the disk upon both sides. 

The disk and the valve proper are permanently attached to 
each other. Above the disk, and in the main casing which sur¬ 
rounds the valve, is located a small auxiliary valve, loaded, by 
means of a spring, to the pressure required. The lower end 
of this auxiliary valve extends downwards and iixto the disk, be¬ 
ing enlarged somewhat above the area of the auxiliary valve, 































































SAFETY-VALVE TESTS. 


49 


where it enters the disk, (in fact, is a small piston within the 
disk,) hut not quite filling the space. Small holes are made 
upon the top of the valve proper, and into the opening which 
receives the enlarged end of the auxiliary valve, for the pur¬ 
pose of admitting the steam above the disk and upon the under 
side of the auxiliary valve. The operation is as follows: 

The steam passes through the small holes above the valve 
proper, and around the enlarged stem of the auxiliary valve, 
to the upper side of the disk and under the auxiliary valve. 
When the pressure is made to overcome the resistance of the 
spring, the auxiliary valve opens, and the steam above the disk 
is discharged more rapidly than it can pass through the open¬ 
ing, consequently the pressure is reduced upon the upper side 
of the disk, which causes it to rise, lifting the valve proper 
from its seat. The valve proper opens against the pressure 
and upwards. 

The excess obtained on this valve at thirty pounds pressure, 
was from 1 to 1J pounds; at seventy pounds pressure, \ pound. 

Areas exposed, 1.171 square inches; lift, .20 inch. 


30 POUNDS PRESSURE. 


ah 

c5 

eh 


£ 

H 

£ 


.20 


% 


1.171 


S be 
pi g 

I 

1 ^ 
o 


25 

25 


Ph 

o 


30 

30 

30 


a 


29 

271 

281 


70 POUNDS PRESSURE. 


3 


b 5 
dh 
dh 

/5 


.20 


m 


1.171 


§ bb 

s g 

si 


69£ 

65 

65 

65 


& 


70 

69 

70 
70 


70 

641 

641 

671 


a Opened promptly at 30, receded to 291, closing every 2 and 10 seconds for 5 m., when it continued 

;o blow with a tremulous action until closed. Valve striking quite hard against seat. 
b Opened promptly, continuing to blow between 69* and 70 with a tremulous and intermittent 

iction, very unpleasant to say the least. . . „ ' Qftl . - ons 

c Openedkt 30 in 1 m.; 30 in 2 m.; 30 m 3 m.; 30 m 4 m.; 30* m 5 m.; 30* m 6 m.; 30* m 7 m.; 30| 

n d^r8t 3 rr£z 9 Tkec 3 e 1 ded to 68* in 1 m.; 68 in 2 m.; 67 in 3 m.; 67 in 4 m.; 66* in 5 m.; closed at 65* 
n 6 m.; 64J in 7 m.; 64* in 8 m.; 64* in 8* m., and closed; opened at 69. Action of this valve erratic 

bI cf Smmd^Trial .—Receded to 67* in 1 m.; 66 in 2 m.; 65 in 3 m.; 65* in 4 m.; closed; opened and 
ilosed at 69*. Opened again and receded to 66* in 6 m.; 66 m 8 m.; 65| in 9 m.; 65 4 m 10 m. Action 

'VSalseiUoVo*, and receded to 29* in 2 m.; 29* in 3 m.; 29* in 5 m.; 29 in 6 m.; 28* in 7 m.; 28| in 8 

o • 28* in 9 m. • closed. Action at first erratic, then steady and even. ... . in 

/Raised to 70*, and receded to 69 in 4 m., closing at 68, 5 times in 6 m.; closing at 67* in 10 m. 

Lotion erratic. 


































50 


SAFETY-VALVE TESTS. 


Differential Tests. 


02 

0 


Ti 

a 

0 

2 

0 


82 

70 

78 

71 

78 

71 

78 

71 

78 

71 

78i 

71 


b£ 

•S £ 

bfi i? 

.9 ft 

§ bfi 

ft .9 


Mean. 


>al. 10 


Mean. 


.20 


50 


Mean. 


1.171 


GQ r— 1 

2 o a 

S ^ © C 

S 2 I 
1«a 


2 0 - 


12 

7 

7 

7 

7 

7i 


79£ 

80 

80J 

80 

81 


m 

72 

72 

72 

72 


H0 

g 

bfi 

■a | 

be 0 

.9 ft 

g bJD 

ft 9 


Mean. 


^ 1.10 


Mean. 


.20 


50 

P 


Mean. 


1.171 


| ® .g 
© *2 0 
h 0 n 


» p ^ . 

>5 05 

0^0© 
© 0 > 0 
£ 0 ® 0 
© ® 'S S 

tifl 
| -2 

| 2i53 

*« 0 t» 0 

P 


8 

8 

8* 

8 

9 


a The action of this valve showed plainly that it discharged the steam very fast, but in no way was 
it different from former tests. Area obtained by manipulating the graduating plate until the pressure 
remained steady in both pipe and boiler. 


CASE & BAILLIE’S, (REACTIONARY,) SPRING-LOADED. 














































































































































SAFETY-VALVE TESTS. 


51 


Area of valve-opening, 5 square inches; main seat, flat. 

A lip-seat, made at an angle of 45 degrees to the centre line 
of valve axis, extends beyond the valve-seat proper, and a cor¬ 
responding angular seat is made in the valve casing, against 
which the steam impinges after passing the valve-opening proper. 

The object sought through this extended angular seat, is to 
cause a reaction on the valve and effect a greater lift. 

The excess obtained on this valve, at thirty pounds pressure, 
(the only pressure at which it was tested,) was 8f pounds in 
two minutes. The spring was not suitable for any of the re¬ 
quired pressures-, except on the differential test , when its action 
was much better, making a small excess. 


WALTER DAWSON’S (ANNULAR) SPRING-LOADED SAFETY-VALVE. 



External diameter, 4 inches; internal, 3.25 inches. Steam 
passim* outside of and through the valve to the atmosphere. 








































52 


SAFETY-VALVE TESTS. 


Tried at seventy pounds pressure, made an excess of 4J 
pounds in five minutes, and closed at 64 pounds. Opening and 
closing points difficult to define. Spring not suitable for either 
thirty or seventy pounds. 

No areas recorded. 


HARDIN’S, (DOUBLE-SEATED,) LOADED BY WEIGHTS DIRECT. 



The ratio of the difference between the areas of the two 
openings is so arranged that, by the addition of one pound 
weight to the valve-stem, one pound additional pressure per 
square inch will be necessary to open it. 












































































SAFETY-VALVE TESTS. 


53 


The inventor claims for this valve simplicity of arrangement 
of parts; that it will relieve a boiler of all excess of pressure 
quicker and more freely than other valves; that it will raise 
exactly at the pressure desired, and reseat instantly on the 
pressure receding below the point at which it opens; that it is 
not liable to be acted upon by the rust and dirt from a boiler. 

There is no necessity for any particular description being 
made of this valve, the drawing is sufficiently plain; but the 
committee desire to state that the claims of the inventor were 
not sustained by the test made; the excess was large, and it 
did not close until the pressure in the boiler receded 15J 
pounds below the opening point. 

This valve was tried at 70 pounds pressure; made an excess 
of 9 J pounds in 7 minutes, and was closed by blowing off the 
steam through the main valve attached to the boiler at a 
pressure of fifty-five pounds. Opening and closing point un¬ 
certain. Leaked badly. 


HIGINBOTHAM’S, (COMBINATION,) SPRING AND LEVER-LOADED. 

Area of valve-opening, 5 square inches; flat seat. The 
short end of the lever, instead of being held firmly to the casing 
of the valve, was supported by a spring enclosed in a circular 
recess cast in the main casing of the valve, and compressed 
just sufficient to balance the weight on the opposite end of the 
same lever. 

Both spring and weight being adjusted to a required pressure, 
any attempt to increase the same by moving the weight from 
the valve results in diminishing the resistance to the pressure, 
the same as though the weight had been moved towards the 
valve, by bringing the under edge of the lever to bear upon a 
point or secondary fulcrum, located between the weight and 
the valve. 

The only means by which an increase of pressure can fairly 
be obtained is by increasing the tension of the spring in the 



54 


SAFETY-VALVE TESTS. 


HIGINBOTHAM’S, (COMBINATION,) SPRING AND LEVER-LOADED. 



casing and moving the weight further from the valve. When 
this valve is fastened to a boiler, the spring is protected from 
all interference. 

This valve not being adjusted at any of the required press¬ 
ures, its efficiency was not ascertained. 














































SAFETY-VALVE TESTS. 


55 


KIMBLE & BOSTICK’S, (REACTIONARY,) SPRING-LOADED. 



Area of opening, 5 square inches; angle of seat, 45 degrees 
to the centre line of the axis of the valve. 

The reaction in this valve is obtained by means of an over¬ 
hanging adjusted lip, curved downwards, and a recess in the 
main casing to the valve, the steam, in its passage out, striking 
against these parts. 

The main peculiarity in this valve consists in the spring be¬ 
ing located within the valve and below its seat. The spring is 
compressed by means of a short screw passing through the out¬ 
side cap, which is secured to the main casing. The steam 






















































































































56 


SAFETY-VALVE TESTS. 


passes up through the space between this pendent portion of 
the valve and the main casing to the valve opening. 

The action of this valve, when under pressure of steam, is 
best described in the notes attached to the table recording the 
tests. Lift not obtained. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

a 5 

8* 



29 

29£ 

30 

b 5 

9 



684 

70 

69 






c 5 

34 

i 


694 

70 

694 








d5 

_2 

2 



2 

68 

69 

684 








5 




68£ 

69£ 

68£ 














a Raised to 30£ in 1 m. ; 32 in 2 m.; 33£ in 4 m.; 35 in 6 m.; 36 in 7 m.; 37 in 8 m.; 38| in 10 m., con¬ 
tinuing. The action of this valve was prompt, but the means to secure it from changing being insuffi¬ 
cient, the trials could not be extended. 

b Raised to 73 in 1 m.; 74 in 2 m.; 76 in 3 m.; 77 in 4 m.; 79 in 4? m., when the trial ceased; time, 4£ m. 

c Opened promptly, and raised to 71£ in 2 m.; 72 in 3 m.; 72£ in 4 m.; 72§ in 5 m.; 72i in 6 m.; 72| in 
7 m.; 73 in 8 m.; 73£ in 9 m., continuing slowly. Action vibrating and tremulous. Adjusting screw, 
as in first trial, worked out. 

d Receding to 68£ and closed; opened and receded to 68f in 3 m.; raised to 69£ in 4 m.; 70 in 5 m.; 70* 
in 6 m.; 70£ in 7 m.; 70| in 8 m.; 70J in 9 m.; 72 in 10 m. 

Second Trial. —Receded to 69£, and held at that pressure for 3 m., closing at 68J in 5 m., when the trial 
ceased. Action same as former trials—erratic, vibrating, and tremulous. 


LYNDE’S, (DISK,) SPRING-LOADED. 

Area of opening, 5 square inches; seat, nearly flat, and quite 
wide. 

This valve has a convexed disk attached to the stem of the 
valve, and above the same, with an area considerably larger 
than that of the valve proper, for the escaping steam to operate 
against, and assist in lifting the valve proper. 

This disk, at its periphery, nearly touches the casing of the 
valve-seat at its upper edge, and at some distance from the valve 
proper, forming a chamber above the valve. 

This disk is perforated with several small holes, and also has 
a register attached to it, for the purpose of regulating the 
opening and closing points of the valve, and controlling the 
escape of the steam. 

































SAFETY-VALVE TESTS. 


57 


The excess obtained on this valve, at thirty pounds pressure, 
was from ^ to 4J pounds; at seventy pounds pressure, no ex¬ 
cess was obtained. 



On a 10-inch valve, an excess of \ pound was obtained at 
thirty pounds pressure, but none at seventy pounds pressure. 

Lift at 30 pounds, .14; area, 1.110 square inches. Lift at 
70 pounds, .07; area, .555 square inch. 





































































58 


SAFETY-VALVE TESTS. 


Trial Tests. 


30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

5 

a\\ 

.14 

1.110 

29| 

30 

b 29 

5 


.07 

.555 


69f 

65 

5 

H 



29! 

30 

26! 

5 





70f 

67! 










/10 

! 



30 

30 

27 

5 





71 

69f 







5 





70 

69f 








5 




c69 

70 

67 f 








10 




d6 9! 

70 

66f 








e 10 




70 

70 

68 
















a Discharged all the steam at this excess. 

b Points of opening and closing not clear. 

c Commenced to blow light at 69, popped at 70, receded to 67, oscillating between this and 69J for 10 
minutes. 

d Opened promptly, and receded to 67£ in 1 m.; 67J in 2 m.; 67 in 3 m.; 67 in 4 m.; 67 in 5 m.; 67 in 
6 m.; 66 $ in 7 m.; 66 $ in 8 m.; 66 | in 9 m.; 66 | in 10 m. Action very tremulous, as if on the point of 
closing, as it was. 

e Receded to 68 $- in 1 m.; 68 $ in 2 m.; 68 £ in 3 m.; 68 J in 4 m.; 685 in 5 m.; 681 in 6 m.; 685 in 7 m.; 
685 in 8 m.; 68 $ in 9 m.; 68 $ in 10 m. Action very steady, opening and closing promptly. 

/Receded to 29J in 1 m.; raised to 29J in 2 m.; 29$ in 3 m.; 29| in 4 m.; 29$ in 5 m.; 30 in 6 m.; 30£ 
in 7 m.; 301 in 8 m.; 301 in 9 m.; 30j in 10 m. Action very steady. 


Differential Tests. 





AREA OF VALVE, 

5, 



AREA OF VALVE, 10. 

Pressure in boiler. 

Pressure under valve. 

Area of opening in gradu¬ 
ating plate. 

Lift of valve. 

Effective area. 

Difference between press¬ 
ure in boiler and under 
valve, noted every min¬ 
ute for 10 minutes. 

Pressure in boiler. 

Pressure under valve. 

Area of opening in gradu¬ 
ating plate. 

Lift of valve. 

JL 

Effective area. 

Difference between press¬ 
ure in boiler and under 
valve, noted every min¬ 
ute for 10 minutes. 




Mean. 

Mean. 

Mean. 






Mean. 

Mean. 

Mean. 



82 

70 

4 





' 12 

80 

69! 






r 10! 

77! 

68 






9! 

81! 

69! 






12 

77! 

67f 






9f 

82! 

69! 






13£ 

77! 

67! 






10 

83! 

69! 






14! 

78f 

67 f 






11 

84 

69! 






14f 

78! 

69! 


.cl. 20 

.07 

.555 

< 

9 

83! 

69f 


>al. 33 

.07 

.555 

< 

13f 

78! 

69! 






8f 

83! 

69f 






13! 

78! 

69! 






9! 

82f 

69f 






13 

78! 

69 



' 



9! 

83 

69f 






13! 

78! 

69 






9! 

82f 

69f 



1 



• 13 

78! 

69 






1 9! 

80 

69! 

> 


1 



l 10! 


a (Spring.) The increase of boiler pressure was checked by increasing the opening in the pipe 
until it was reduced to the starting point. 

c The action of this valve was very even, and obtained by manipulating the graduating plate until 
the nressure remained standing in both pipe and boiler, with valve discharging freely. 









































































XV^XXNXX^X 


SAFETY-VALVE TESTS. 


59 


LASSOE’S, (COMBINATION,) SPRING AND LEVER-LOADED “ BELL- 

CRANK.” 







































































































































































































































































































60 


SAFETY-VALVE TESTS. 


Area of opening, 5 square inches; flat seat. The valve is 
held to its seat by means of a lever, to the end of which is 
attached a spring-balance. 

From the end of this lever, extending downwards, is a bar 
which connects with the short end of a toggle or bell-crank 
lever, to the long end of which the spring-balance is attached, 
and in the position to act upon the main lever through the con¬ 
necting-bar above mentioned whenever the pressure in the 
boiler overcomes the resistance of the spring-balance, and assists 
in raising the valve from its seat. The object of this arrange¬ 
ment is to get an increase of lift to the valve. 

Excess obtained on this valve at thirty pounds pressure, J 
pound; at seventy pounds no excess was obtained. Areas not 
attainable. 

Its closing points were from 6§ to 8J pounds below its 
opening point. 


30 POUNDS PRESSURE. 


Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

ab 

i 



29 

m 

28 














































70 POUNDS PRESSURE. 


◄ 


Excess. 

Lift of valve. 

Effective area. 


























Commenced 

blowing. 

Opened wide. 

Seated at. 

64 

70 63f 

65 

70 | c61£ 

65 

70 62£ 

65 

70 68 

65 

69 61 

65 

69 ' 60£ 

65 

70 1 62£ 


65 

5 

5 

db 

5 

5 

5 


a Receding to 28 and closed, opening again at 30£; continued at this point 6 m., and closed at 28. 
b Receding to 65 in 1 m.; 64 in 2£ m., and closed, opening in 3# m.; closed in 6 m.; opened again in 
7| m., and closed in 10 m. at 63J. 

c Receded to 66 in 1 m.; 63 J in 2 m.; 621 in 3 m.; 61J in 4 m.; 611 in 5 m., and closed; opened at 70 
in 7 m., and receded to 651 in 8 m.; 64| in 9 m.; 63J in 10 m. The opening and closing points not well 
defined. 

d This trial was after the valve had been readjusted. On the third trial it closed in 3 m. from the 
start, and on the 4th trial in 5 m.; the points of opening and closing not well defined; leaking badly. 




































61 


-SAFETY-VALVE 


TESTS. 


Jji ffrrrnlial T&U. 



r -x 


r. r - 
r. _r — 






S2 

70 





p 1 2 

73| 

65 





| r 

75 

64 





11 

74 

63* 





74f 

74y 

&H 

i 

,■ L30 



m 

10 

74 i 

73* 

G&£ 

654 


. L30 




74 

64i 





9i 

1 i 

64 






T3i 

64^ 

J 




L 9 



J 




l 


9 

10 

13 


a The action of this Til re was very free: ire-4 obtained by e Ar 4 p~ ~ i rf r g the grsriniting plate on til 
the pressure remained jUndfag in both pipe and bake, with val—e cAchir-git:g freely. 

lift could not be obtained. 



k4» iH- 







































































































































62 


SAFETY-VALVE TESTS. 


External diameter of annular space, 2.52 inches]; internal 
diameter of annular space, 2 inches; flat-faced. 

Steam discharged at the outer edge of valve and through 
apertures in the valve itself. This valve is guided to its seat 
by means of central spindle extending below its seat. 

No excess was obtained on this valve at either pressure. 

Lift at thirty pounds pressure, .10 inch; at seventy pounds, 
.06 inch. 

Areas exposed at thirty pounds, 1.42 square inches; at sev¬ 
enty pounds, .84 square inch. 

Closed, when opening at thirty pounds, at 27; when opening 
at seventy pounds, at 60J, 65, and 59 \ pounds. 



a Receded to 28* in 4 m.; 29J in 5 m.; 29J in 7 m.; 29f in 9 m.; continuing to the close. 
b Receded to 59J in 2 m., closing and opening 4 times at this point in the 10 minutes’ trial, 
c Receded to 67 in 1 m.; 60* in 3 m.; closed, opening in 5 m.; closing again in 7£ m. at 60|; continu¬ 
ing in this way to end of trial. Valve working free and with no jar or disturbance. 

d Opened promptly at 69|; receded to 65, and closed in \ m. j opening and closing at the points 11 
times in the trial of 10 m.; action easy. 


Differential Tests. 


5 SQUARE-INCH VALVE. 


Pressure in boiler. 

Pressure under valve. 

Area of opening in grad¬ 
uating plate. 

Lift of valve. 

Effective area. 

Difference between press¬ 
ure in boiler and under 
valve, noted every min¬ 
ute for 10 minutes. 



Mean. 

Mean. 

Mean. 



82 

70 

-s 





f 12 

76 

66 






10 

75! 

65 


ll.32 

.06 

.840 


10i 

74! 

64 






10£ 

74! 

63! 





l 11 


5 SQUARE-INCH VALVE. 


Pressure in boiler. 

Pressure under valve. 

Area of opening in grad¬ 
uating plate. 

Lift of valve. 

Effective area. 

Difference between press¬ 
ure in boiler and under 
valve, noted every min¬ 
ute for 10 minutes. 



Mean. 

Mean , 

Mean. 



74! 

64 






r io! 

74! 

63| 






ii 

74} 

63! 


[>1.32 

.06 

.840 


10! 

74} 

63 






’ Hi 

74 

62f 

J 





1 Hi 


a. On this trial the adjusting screws worked loose, causing the valve to seat later, and the pressure 
to run down in the pipe. ' 


























































SAFETY-VALVE TESTS. 


63 


NELSON, FINKLE & CO.’S LEVEE SAFETY-VALVE. 



Composition seat, flat; area of opening, 5 square inches. 

The only peculiarity attached to this valve is its seat, being 
composed of a substance claimed to be anti-corrosive. It was 
tested at 32 J pounds, the only pressure to which it was adapted; 
made an excess of 3J pounds in six minutes, continuing at this 
point to the end of the test, and closing at 29J pounds. Lift, 
.20 inch; area, 1.586 square inches. 





























































64 


SAFETY-VALVE TESTS. 



30 POUNDS PRESSURE. 

70 POUNDS PRESSURE. 

Area of valve. 

GO 

s 

w 

M 

H 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

7 

Seated at. 

a5 

16 

.08 

.457 

29 

30 

30 

b 5 

4 

.05 

.284 

• 69 

70 

61 


a At this excess (16) not all the steam discharged. & Receded to 69, and then raised to 74. 


ORME’S, (REACTIONARY,) SPRING-LOADED. 

Area of valve, 5 
square inches; nar¬ 
row flat seat, with 
the valve extending 
beyond the seat 
proper, and at an 
angle of 45 degrees 
to the centre line of 


axis. 

Secured to the 
outside of the casing 
is an adjustable ring 
or seat, correspond¬ 
ing to the extending 
portion of the valve. 
By manipulating this 
adjustable ring or 
seat, the opening, 
closing, and lift of 
the valve can, with¬ 


in a very narrow 
limit, be regulated. 
The excess ob¬ 
tained on this valve at thirty pounds pressure was 6 pounds; 
at seventy pounds pressure, 4 pounds. 

Areas exposed at thirty pounds, .457 square inch; lift, .08 
inch. At seventy pounds, .284 square inch; lift, .05 inch; 
closing at 61 pounds below the opening pressure. 























































SAFETY-VALVE TESTS. 


65 


Differential Tests. 



a The operation of this valve showed plainly that it could not control the steam at any of the press¬ 
ures and areas; it was continually on the rise. Opening and closing points not clear. 


RICHARDSON’S, (REACTIONARY,) SPRING-LOADED. 

Five square inches area of valve-opening. Angle of valve- 
seat, 45 degrees to the centre line of the axis of spindle. 

The steam, in escaping through the ground-seat, strikes 
against the extended lip of the valve, which is curved down¬ 
ward, forming an annular chamber and an adjustable ring, 
with a chamfered edge, thereby forcing the valve proper fur¬ 
ther from its seat than the distance due the pressure and 
volume of the escaping steam. 

A diaphragm, either of metal or rubber, is located between 
the valve and the spring, and so arranged that no steam can 
come in contact with the latter, thereby protecting it from the 
corrosive influence of the steam. 

One of these valves has two springs, arranged so as to exert 
their strength and force in opposite directions; that is— 

The lower spring holds the valve down against its seat, and 
the upper one lifts it from its seat, so that the valve proper will 
open at a pressure equal to the difference between the adjusted 
power of the springs. For example : 

5 

























66 


SAFETY-VALVE TESTS. 


RICHARDSON’S, (REACTIONARY,) SPRING-LOADED. 



























































































SAFETY-VALVE TESTS. 


67 


The lower spring is compressed sufficiently to hold the valve 
down at one hundred pounds pressure, and the upper spring 
compressed to exert one-tenth of that force in an opposite direc¬ 
tion; that is, raise the valve. The valve will then lift at 100 
less 10 = 90 pounds pressure. 

The drawing represents a lock-up safety-valve, with means 
upon the outside to lift it from its seat. These valves are made 
with either single or double springs, and without the lock-up 
arrangements. These valves also have an arrangement by 
which they can be retained in their seats whenever it becomes 
necessary to do so; such, for instance, as to apply the hydro¬ 
static test to the boiler. 

The excess obtained on these valves at thirty pounds pressure 
was from \ to 7 pounds; at seventy pounds pressure, from 
to 3§ pounds. 

Areas exposed at thirty pounds, .869,1.171, and 1.455 square 
inches; lifts, .15, .20, and .25 inch. 

At seventy pounds, .691 square inch; lift, .12 inch. 

An examination of the table recording the tests made upon 
these valves will show that the excesses were varying, and that 
in some instances none at all was obtained. 


30 POUNDS PRESSURE. 


70 POUNDS PRESSURE. 


Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at. 

Area of valve. 

Excess. 

Lift of valve. 

Effective area. 

Commenced 

blowing. 

Opened wide. 

Seated at . 

a 5 


.25 

1.455 

29 

30 

29j 



Failed. 





65 

34 

.25 

1. 455 

19 

20 

184 

d 5 

3£ 



694 

70 

67 

G 5 

7 

. 15 

.869 

294 

30 

28. 

/5 

14 

.12 

.691 

694 

70 

68 

€ 5 




28£ 

28f 

274 

5 




<7694 

70 

66£ 

65 

i 



194 

20 

19 






4 












i 5 

5i 

.20 

1.171 

29 

30 

284 








i 5 


.20 

1.171 

29 

30 

274 








65 


.20 

1.171 

34 

35 

33 









a Receded to 29f in 1 m.; 30 in 5 m.; 30J in 8 m.; 30£ in 10 m. 

b Set at 20; raised to 20£m 2 m.; 21 in 3 m.; 22 in 5 m.; 22£ in 6 m.; 23 in 8 m.; 23J in 10 m., contin¬ 


uing slowly to rise. 






























68 


SAFETY-VALVE TESTS. 


c (Combination spring.) Raised to 30? in 2 m.; 31 in 2? m.; 32 in 3? m.; 33 in 5 m.; 33Jin 6 m.; 34 in 
7 m.; 35 in 7? m.; 36 in 8 m.; 37 in 10 m., continuing slowly. 

d Receded to 69 in 1 m.; raised to 70 in 3 m., 70? in 4 m.; 71 in 5 m.; 71$ in 6 m.; 72J in 8 m.; 73J in 
10 m; rising very slow. 

e Receded to 284 in 1 m.; 28£ in 2 m.; 284 in 3 m.; 284 in 4 m.; 28$ in 5 m.; 28$ in 6 m.; 28J in 7 m. 
28f in 8 m.; 28| in 9 m.; 28| in 10 m.; steady. 

/Receded to 68 in 1 m.; 68 in 2 m.; 68 | in 3 m. ; 681 in 4 m.; 68 | in 5 m.; 69| in 6 m.; 70J in 7 m.; 70| 
in 8 m.; 71 in 9 m.; 71J in 10 m.; action steady. 

gSecond Trial .—Receded to 67?in 1 m.; 67 in 2 m.; 67$ in 3 m.; 67J in 4 m.; 67? in 5 m.; 67J in 6 m.; 
68 in 7 m.; 685 in 8 m.; 68 ? in 9 m.; 684 in 10 m.; action steady. 
h Experimental trial at 20 pounds, with very light spring. 

i Raised to 32 in 3 m.; 33 in 4 m.; 34 in 5 m.; 34J in 7 m.; 34| in 8 m.; 35 in 9 m.; 35£ in 10 m.; 
opened to control the steam at maximum excess. 
j Receded to 29?, and raised to 30 in 2 m.; receded to 29? in 7 m.; continued at this. 
k Receded to 34 in 1 m.; 344 in 3m.; 34$ in 9 m; 34£ in 10 m; valve set at 30 pounds. 


Differential Tests. 


■ 

Pressure in boiler. 

Pressure under valve. 

Area of opening in gradu¬ 
ating plate. 

Lift of valve. 

Effective area. 

Difference between press¬ 
ure in boiler and under 
valve, noted every min¬ 
ute for 10 minutes. 

Pressure in boiler. 

Pressure under valve. 

Area of opening in gradu¬ 
ating plate. 

Lift of valve. 

] 

Effective area. 

Difference between press- 

ure in boiler and under 

valve, noted every min¬ 
ute for 10 minutes. 



Mean. 

Mean. 

Mean. 


i 


Mean. 

Mean. 

Mean. 



80 

70 

1 



r 10 

79£ 

69£ 




1 

r ioi 

79 

69 




! io | 

79i 

69i 

1 



! 

10 



'} 1.25 

.12 

.691 

< 



1.25 

.12 

.691 

j 


79 

68| 

j 



10i 

79f 

69£ 

j 



> 

10£ 

79£ 

69 

J 



l 1( h 

79f 

69i 

i 

J 




L io* 


ROCHOW’S, (PISTON,) LOADED BY LEVER AND WEIGHT. 

Area of valve-opening, 5 square inches; angle of valve-seat, 
45 degrees to the centre line of its axis. The piston is of a 
larger area than that of the valve proper, is located some dis¬ 
tance below the valve-seat, and attached to the valve by means 
of a spindle extending downwards. Between the piston and the 
valve proper is a space which may be called a reduction chamber. 
The steam is admitted into this chamber through apertures in 
the surrounding casing just above the top of the piston, and 
when the pressure exceeds the resistance of the weight on the 
valve proper, and lifts it from its seat, it brings up with it this 
piston. The apertures in the casing are, by this , action of the 
valve, partially closed by the piston, and the steam is gradually 

























SAFETY-VALVE TESTS. 


69 


ROC HOW’S, (PISTON,) LOADED BY LEVEE AND WEIGHT. 



being cut off, and thereby reducing the pressure in the reduc¬ 
tion chamber, and upon the upper side of the piston. This 
reduced resistance to the rising of the piston, and the area ex¬ 
posed to the pressure of the steam in the boiler being some¬ 
what in excess of that of the valve proper, it forces the valve 
further from its seat, where it will remain until the pressure in 
the boiler is sufficiently reduced to allow the piston to fall be¬ 
low the apertures above mentioned, when the valve proper will 
suddenly seat itself. 

The excess obtained on this valve at thirty pounds pressure, 
from f to 1J pounds; at seventy pounds pressure, from 3 to 4 
pounds. 

Areas exposed at thirty pounds, 1.231+ square inches; lift, 
.21 inch. At seventy pounds, 1.231+ square inches; lift, .21 
inch.. 






























TO 


SAFETY-VALVE TESTS 


Trial Tents. 


30 POUNDS PRESSURE. 70 POUNDS PRESSURE. 


c • 

| | 

i 1 i 

< s ^ 

c2 

> 

§ 

8 ^ 

1 i 

4 > 

1 * 1 

— w 

i s 

C | < 

> 

- 

> 

X ^ 

X iz 

2 

| l ^ 

S Sc 

2 n 

► t 

S *5 

g 5 

X cS 

»—4 £ 

C oe 

5 a f .21 

1.231 

28 

30 b 251 5 

c3 .21 

1.231 69 

70 64 

5 .. 


28 

30 2(3-4 5 


. 69 

71 1 <7624 

eb 14 . 


28 

30} 28} fb 

.. 

4 . 

. i 67 

704 66 




a b 

34. 

67 

714 634 











_ ; _ !j 5 


. 64 

70 604 









a Temporary excess, and then receded to 1 pound below 30. 
b Opening and closing point not clear. 

c Temporary excess, and then receded to If pounds below 70. 
d Receded to 66}, continuing at this point for the 10 minutes. 

e [Raised to 30} in 1 m.: 31} in 2 m.; 31} in 3 m.; 31} in 4 m.; 31} in 5 m.. continuing when trial closed. 
/Raised to 71} in 2 m.; 7*2} in 3 m.; 73} in 4 m.; 73} in 5 m.; 73} in 6 m.; 73} in 7 m.; 73} in 8 m.; 74 
in 9 m.. continuing. Opening and closing points not clear. Action steady. 

g Raised to 70} in 1 m.; 70} in 2 m.: 70pin 3 m.; 70} in 4 m.; 71} in 5 m.; 72 in 6 m.; 72} in 7 m.; 73 in 
8 m.; 73} in 9 m.: 73} in 10 m.. continuing. Action same as on trial of 5th instant. 

h Receded to 67 in 1 m.; 67} in 3 m.; 68 in 5 m.; 67} in 8 in.; 67} in 9 m.; 67 in 10 m. Action irregular 
in seating. 


SISSON'S, (REACTIONARY.) SPRING-LOADED 














































































71 



Two valves, Xos. 1 and 2, with 5 and 10 square inches areas, 
respectively. 

Yalve-seat of an inverted Y shape. Yalve Xo. 2, 10 square 
inches area, has a disk attached to the stem of the valve, which 
extends some distance below the valve-seat proper, thereby 
forming a partial reduction chamber. 

Yalve Xo. 1, 5 square inches area; has no disk. 

The excess obtained on valve Xo. 1, at seventy pounds press- 




























72 


SAFETY-VALVE TESTS. 


ure, was 6J pounds, closing at 8J pounds below the opening 
point. 

The excess obtained on valve No. 2, at seventy pounds press¬ 
ure, was 4J pounds, closing at 5J pounds below the opening 
point; no areas recorded. 

These valves were very difficult of adjustment, so far as the 
opening and closing points were concerned. At the expiration 
of the ten minutes’ trial, the excess on both tests was increas¬ 
ing fast. 



a Raised to 72 in 1 m.; 75 in m.; 751 in 5 m., and continued. 

b Receded to 70£ in 1 m.; raised to 71 in 2 m.; 721 in 3 m.; 73£ in 4 m.; 74 in 6 m.; 741 in 10 m., con¬ 
tinuing fast. 
































'AjrTTY-VALVE 




40 






f> 



























































74 


SAFETY-VALVE TESTS. 


This instrument is an attempt to show all the varying press¬ 
ures in a boiler, from one pound to the maximum, by means of 
a piston working within a cylinder, and loaded by a spring and 
lever, so as to allow the piston to rise as the pressure increases, 
operating a pointer rotating upon the face of a dial located upon 
the outside of the casing, and, at the maximum pressure, un¬ 
covering an opening between the boiler and the atmosphere. 

This instrument was tested at sixty pounds; made an excess 
of 5J pounds in 10 minutes, and was forcibly closed at 45 
pounds. 

Its action variable and uncertain. Opening and closing 
points difficult to determine. 

Analysis of the Results obtained on Competing Valves. 


NAME OF VALVE. 


Ashcroft. 

Ashton. 

Boden. 

Cockburn. 

Cockburn (&)... 

Crosby. 

Clemens. 

Chamberlain 

Case & Baillie.. 
Dawson. 

Hodgin ( e ) __ 

Higinbotham (d) 
Hardin. 


AT 30 POUNDS PRESSURE. 


a| 

pj c +-i 

I 


l. no 


1.820 


1. 820 


4 7 

* 26 


27 

27| 
32£ 
26 
29 

1.171 I 29 
' 27 J 


1. 257 j | 
1.580 | 


2.934 


28 
291- 


(26 

18 




} 9. 


25 


2.75 

| 2.75 
| 5.95 
2.5 

} 8.87+ 
9. 25 


} 9.87+ 


AT 70 POUNDS PRESSURE. 




4£ 


9£ I 94 


P 

P 

a 

‘a 

a 

'p 


a .§ 

P 


1.231 


.574 


1.180 


.729 

628 

1.171 


?: 


.920 


1. 427 


r+ o. 


.3 

*53 ^ 
© 'g 


a -a: * * 

a o ® <© 

ZZ, __h o GO 


r65! 
( 67| 
68 £ 

64 

69£ 

67f 

68 £ 


64 
68i 
C 64? 
\ 70 

67£ 


} /3. 62+ 
8. 75 
7.75 


2 . 12 + 


| 5.95 

} 3.37+ 

11.75 


64 | 10.5 

»5£ • j } 

16 !l 14 - 25 


C 55£ 
l 56 


55 


25. 























































SAFETY-VALVE TESTS. 


75 


„ Analysis of the Results obtained on Competing Valves —Continued. 



a No trial. 

b Opened at 35 pounds, at which pressure it had been set and locked by the owner, 
c No results. 

d Would operate only at a pressure of 20 pounds. 
e An extreme area, owing, no doubt, to the form of the stricture. 

/The whole excess made at all the trials, divided hy the number of trials. 
g Opened at 20 pounds. 
h Opened at 65 pounds. 

“ Boden” valve, 7 square inches area. 

“Dawson” valve, 4 and inches diameter, (annular,) with this exception, the 
valves named in the table were all 5 square inches in area. 


JAS. A. DUMONT, 
Supervising Inspector-General, Chairman, 
ADDISON LOW, 
Supervising Inspector, Second District, 

WM. ROGERS, 

Supervising Inspector, Tenth District, 


}> Committee. 

































































, 






/ 








A. 




‘ 














/ 












r-. 







. <« 



—■ 

. 














\ .. 








* 














' 

























' - 


, 




&•* 




















' 

1 1 ‘ 

























1 

-i 






























t > 


































V f 




































• • 














































<• 














































,v J i 

' 




■ 




> V 




I 








. .• • • .V;- - ' 






• I 








. 






















* 






/ I 


' 

* 



















♦ * 




‘ 




























t 

















. 


’ 















1 











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/ 














